Code Golf

#10: Post edited by

trichoplax‭ · 2022-09-30T21:31:12Z (over 1 year ago)
Mark as finalized

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~~Knight safe squares~~

Knight safe squares [FINALIZED]

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided it does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.

# Now posted: [Knight safe squares](https://codegolf.codidact.com/posts/287131)
---
Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided it does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.

code-golf

code-golf finalized

#9: Post edited by

trichoplax‭ · 2022-09-30T21:29:04Z (over 1 year ago)
Remove sandbox questions

Copy Link

Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided it does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
----
~~# Sandbox questions~~
~~- Is there a more useful test case format?~~
~~- Are there any edge cases that should have test cases?~~
~~[]()~~

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided it does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
----

#8: Post edited by

trichoplax‭ · 2022-09-30T21:28:21Z (over 1 year ago)
Remove redundancy in input section

Copy Link

Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
~~- You may take input in the format of your choice provided your choice of input format does not provide additional information that would help solve the challenge~~
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided it does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

#7: Post edited by

trichoplax‭ · 2022-09-30T21:24:41Z (over 1 year ago)
Add image of knight's moves from Wikipedia

Copy Link

Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided your choice of input format does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
~~Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.~~
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided your choice of input format does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
[![Knight's moves shown as dots](https://codegolf.codidact.com/uploads/Q4kXyQDf3HZiX5NWncgRS2Fi)](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "View on Wikipedia")
(thanks to [Wikipedia](https://en.wikipedia.org/wiki/Knight_(chess)#Movement "Wikipedia section on Knight's moves"))
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test case inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

#6: Post edited by

trichoplax‭ · 2022-09-30T17:07:32Z (over 1 year ago)
Input spec golfing

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Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice - perhaps newline separated lines of 8 characters, or 8 strings of 8 characters, or a string of 64 characters, or 64 strings of 1 character - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice provided your choice of input format does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

#5: Post edited by

trichoplax‭ · 2022-09-29T12:28:02Z (over 1 year ago)
Clarify input section and include example in test cases

Copy Link

Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input in the format of your choice - perhaps newline separated lines of 8 characters, or 8 strings of 8 characters, or a string of 64 characters, or 64 strings of 1 character - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"******N*",
"N*******",
],
47
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

#4: Post edited by

trichoplax‭ · 2022-09-29T00:12:22Z (over 1 year ago)
Explain knight's move for completeness

Copy Link

Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
~~- The square is not a knight's move away from a knight~~
- The square does not contain a knight
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square does not contain a knight
- The square is not a knight's move away from a knight.
A knight's move is either of:
- 2 squares horizontally (left or right) and 1 square vertically (up or down)
- 1 square horizontally (left or right) and 2 squares vertically (up or down)
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

#3: Post edited by

trichoplax‭ · 2022-09-29T00:06:55Z (over 1 year ago)
Add sandbox questions

Copy Link

Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square is not a knight's move away from a knight
- The square does not contain a knight
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square is not a knight's move away from a knight
- The square does not contain a knight
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.
---
# Sandbox questions
- Is there a more useful test case format?
- Are there any edge cases that should have test cases?
[]()

#2: Post edited by

trichoplax‭ · 2022-09-29T00:04:10Z (over 1 year ago)
Remove redundant integer confusion

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Raw

Markdown

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
~~- An integer from 0 to 64, indicating the number of squares that satisfy both of:~~
- The square is not a knight's move away from a knight
- The square does not contain a knight
~~- You are not constrained to using an integer type - for example, a float or string that contains the required integer (and nothing else) is acceptable~~
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.
## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge
## Output
- A number from 0 to 64, indicating the number of squares that satisfy both of:
- The square is not a knight's move away from a knight
- The square does not contain a knight
## Example
The following example input has knights represented by `N` and empty squares represented by `*`.
```text
********
********
**N*****
********
********
********
******N*
N*******
```
Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).
```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```
So for this example, the output would be `47`.
## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.
```text
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
64
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
0
],
[
[
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
"N*N*N*N*",
"*N*N*N*N",
],
0
],
[
[
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
"N***N***",
"*N***N**",
"**N***N*",
"***N***N",
],
16
],
[
[
"N*******",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
61
],
[
[
"******N*",
"********",
"********",
"********",
"********",
"********",
"********",
"********",
],
60
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"********",
"*****N**",
],
59
],
[
[
"********",
"********",
"********",
"********",
"********",
"********",
"*N******",
"********",
],
59
],
[
[
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
"********",
],
57
],
[
[
"********",
"********",
"**N*****",
"********",
"********",
"********",
"********",
"********",
],
55
],
[
[
"********",
"********",
"****N***",
"********",
"***N****",
"********",
"********",
"********",
],
48
],
[
[
"********",
"********",
"***N****",
"*****N**",
"**N*****",
"****N***",
"********",
"********",
],
36
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"NN*NNN*N",
"NNNN*NNN",
"NN*NNN*N",
"NNN*N*NN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNN*N*NN",
"N***NN*N",
"*NNN*NNN",
"NN*NNN*N",
"*NN***NN",
"N*N*NNNN",
"NNNNNNNN",
],
2
],
[
[
"*NNNNNNN",
"NN*NNNNN",
"N*NNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNN*N",
"NNNN*NNN",
"NNNNN*N*",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNN*N*N",
"NNN*NNN*",
"NNNNN*NN",
],
1
],
[
[
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"*N*NNNNN",
"NNN*NNNN",
"N*NNNNNN",
"NNN*NNNN",
],
1
],
[
[
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
],
[
[
"N*N*NNNN",
"*NNN*NNN",
"NN*NNNNN",
"*NNN*NNN",
"N*N*NNNN",
"NNNNNNNN",
"NNNNNNNN",
"NNNNNNNN",
],
1
]
```
> Explanations in answers are optional, but I'm more likely to upvote answers that have one.

#1: Initial revision by

trichoplax‭ · 2022-09-29T00:02:18Z (over 1 year ago)

Copy Link

Raw

Markdown

Knight safe squares

Given a chess board with some knights on it, say how many squares are neither attacked by a knight nor containing a knight.

## Input
- An 8 by 8 grid where each square is either a knight or empty
- You may choose to take input with any 2 distinct characters representing a knight and an empty square
- You may take input as newline separated lines of 8 characters, or as a 2d data structure, or as 8 1d data structures - provided your choice of input style does not provide additional information that would help solve the challenge

## Output
- An integer from 0 to 64, indicating the number of squares that satisfy both of:
  - The square is not a knight's move away from a knight
  - The square does not contain a knight
- You are not constrained to using an integer type - for example, a float or string that contains the required integer (and nothing else) is acceptable

## Example
The following example input has knights represented by `N` and empty squares represented by `*`.

```text
********
********
**N*****
********
********
********
******N*
N*******
```

Here it is again with attacked empty squares marked as `a`. The required output is the number of remaining squares (the number of squares still showing `*`).

```text
*a*a****
a***a***
**N*****
a***a***
*a*a*a*a
*a**a***
**a***N*
N***a***
```

So for this example, the output would be `47`.

## Test cases
Test cases inputs are given as 8 strings of 8 characters, followed by the output as an integer. Knights are represented by `N` and empty squares are represented by `*`.

```text
[
    [
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
    ],
    64
],
[
    [
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
    ],
    0
],
[
    [
       "N*N*N*N*",
       "*N*N*N*N",
       "N*N*N*N*",
       "*N*N*N*N",
       "N*N*N*N*",
       "*N*N*N*N",
       "N*N*N*N*",
       "*N*N*N*N",
    ],
    0
],
[
    [
       "N***N***",
       "*N***N**",
       "**N***N*",
       "***N***N",
       "N***N***",
       "*N***N**",
       "**N***N*",
       "***N***N",
    ],
    16
],
[
    [
       "N*******",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
    ],
    61
],
[
    [
       "******N*",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
    ],
    60
],
[
    [
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "*****N**",
    ],
    59
],
[
    [
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
       "*N******",
       "********",
    ],
    59
],
[
    [
       "********",
       "**N*****",
       "********",
       "********",
       "********",
       "********",
       "********",
       "********",
    ],
    57
],
[
    [
       "********",
       "********",
       "**N*****",
       "********",
       "********",
       "********",
       "********",
       "********",
    ],
    55
],
[
    [
       "********",
       "********",
       "****N***",
       "********",
       "***N****",
       "********",
       "********",
       "********",
    ],
    48
],
[
    [
       "********",
       "********",
       "***N****",
       "*****N**",
       "**N*****",
       "****N***",
       "********",
       "********",
    ],
    36
],
[
    [
       "NNNNNNNN",
       "NNN*N*NN",
       "NN*NNN*N",
       "NNNN*NNN",
       "NN*NNN*N",
       "NNN*N*NN",
       "NNNNNNNN",
       "NNNNNNNN",
    ],
    1
],
[
    [
       "NNNNNNNN",
       "NNN*N*NN",
       "N***NN*N",
       "*NNN*NNN",
       "NN*NNN*N",
       "*NN***NN",
       "N*N*NNNN",
       "NNNNNNNN",
    ],
    2
],
[
    [
       "*NNNNNNN",
       "NN*NNNNN",
       "N*NNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
    ],
    1
],
[
    [
       "NNNNNN*N",
       "NNNN*NNN",
       "NNNNN*N*",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
    ],
    1
],
[
    [
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNN*N*N",
       "NNN*NNN*",
       "NNNNN*NN",
    ],
    1
],
[
    [
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "*N*NNNNN",
       "NNN*NNNN",
       "N*NNNNNN",
       "NNN*NNNN",
    ],
    1
],
[
    [
       "*NNN*NNN",
       "NN*NNNNN",
       "*NNN*NNN",
       "N*N*NNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
    ],
    1
],
[
    [
       "N*N*NNNN",
       "*NNN*NNN",
       "NN*NNNNN",
       "*NNN*NNN",
       "N*N*NNNN",
       "NNNNNNNN",
       "NNNNNNNN",
       "NNNNNNNN",
    ],
    1
]
```

> Explanations in answers are optional, but I'm more likely to upvote answers that have one.

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