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Activity for radarekā€­

Type On... Excerpt Status Date
Edit Post #286079 Initial revision 2 months ago
Answer A: Solve Goldbach's Conjecture
Ruby, 62 bytes require'prime';f=->n,k=0{n.prime?&&k.prime?? [n,k]:f[n-1,k+1]} Attempt This Online!
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2 months ago
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3 months ago
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3 months ago
Comment Post #285743 @#53310 Thanks for spotting it. Fixed.
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4 months ago
Edit Post #285743 Post edited:
4 months ago
Edit Post #285743 Initial revision 4 months ago
Answer A: Golf a FRACTRAN interpreter
Ruby, 44 bytes ->p,n{n=I while I=p.find{1n%1==0};n.toi} Attempt This Online!
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4 months ago
Edit Post #285708 Initial revision 4 months ago
Answer A: Stairs? Stairs! Stairs.
Ruby, 50 bytes ->n{n.times{puts (' '(n-1)+'/'+'##'1)[3..]}} Attempt This Online!
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4 months ago
Edit Post #285496 Post edited:
4 months ago
Edit Post #285707 Initial revision 4 months ago
Answer A: Operation "Find The Operator"
Ruby, 57 bytes ->a,b,c{%w[+ - / % ].select{c==a.send(1,b)rescue p}} Attempt This Online!
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4 months ago
Comment Post #285331 However, your code and mine suggestion don't work with input `*,0,*` (division by 0). The error must by properly handled.
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4 months ago
Comment Post #285692 Unfortunately this does not work for input 0, 2 and 0, 2. ``` f=->a,b{a|b==2?5:a+b} f[0, 2] # => 5 ```
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4 months ago
Edit Post #285706 Initial revision 4 months ago
Answer A: Make $2 + 2 = 5$
Ruby, 20 bytes ->a,b{4[a]4[b]+a+b} Attempt This Online!
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Edit Post #285668 Post edited:
4 months ago
Edit Post #285668 Initial revision 4 months ago
Answer A: Given the preorder and the inorder of a tree, output the postorder
Ruby, 75 72 bytes f=->((e,r),n){(i=n.index e)?f[r[0,i],n[...i]]+f[r[i..],n[i+1..]]+[e]:n} Attempt This Online!
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4 months ago
Edit Post #285667 Initial revision 4 months ago
Answer A: Compute the determinant
Ruby, 35 bytes ->m{require'matrix';Matrix[m].det} Attempt This Online!
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4 months ago
Edit Post #285618 Post edited:
4 months ago
Edit Post #285659 Initial revision 4 months ago
Answer A: Prime Difference
Ruby, 56 bytes ```ruby ->n{require'prime';Prime.eachcons(2).find{2-1>=n}[0]} ``` Attempt This Online!
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Comment Post #283012 @#53607 Ok, make sense.
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4 months ago
Comment Post #285618 @#55346 nice catch! Thanks.
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4 months ago
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4 months ago
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4 months ago
Edit Post #285655 Post edited:
4 months ago
Edit Post #285655 Initial revision 4 months ago
Answer A: Merge two strings
Ruby, 40 bytes ```ruby f=->a,b{b.index(a)==0?b:a[/./m]+f[$',b]} ``` Attempt This Online! If we could assume that string contains only letters and numbers (or to be more specific, no characters like `\t\n\v\f\r \#$()+-.?[\\]^{|}`) then it could be improved to 36 bytes: ```ruby f=->a,b{b...
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4 months ago
Comment Post #281542 What characters can strings include? Only letters (like in examples)? New lines can be included? What about other characters?
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4 months ago
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4 months ago
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4 months ago
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4 months ago
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4 months ago
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Edit Post #285632 Initial revision 4 months ago
Answer A: A number adder, not a death adder
Ruby, 25 bytes ```ruby puts"p #{gets}+gets.toi" ``` P1 - Try this online! P2 - Try this online!
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4 months ago
Edit Post #285631 Initial revision 4 months ago
Answer A: Evens or Odds - you know this one
Ruby, 13 bytes According to the rules, programs should read from STDIN and output to the STDOUT. This is my solution: ```ruby p gets.toi&1 ``` Try this online!
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4 months ago
Edit Post #285630 Initial revision 4 months ago
Answer A: Weave Strings Together
Ruby, 48 45 bytes ```ruby ->w{([p].w''=/$/).zip(w.map(&:chars))''} ``` Try this online! It could be improved to 32 bytes, if every string is represented as an array of characters: ```ruby ->w{([p].w''=/$/).zip(w)''} ``` Attempt This Online!
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4 months ago
Edit Post #285629 Initial revision 4 months ago
Answer A: Are All Elements Equal?
Ruby, 14 bytes ```ruby ->{1|[]in[]} ``` Alternative solution: ```ruby ->a{!(a|a)[1]} ``` Try this online! Couple of other solutions I developed: ```ruby ->a{!a.uniq[1]} # 15 bytes ->{!(1|[])[1]} # 15 bytes ->a{(a|a).one?} # 15 bytes ```
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Edit Post #285623 Initial revision 4 months ago
Answer A: Make my number a set
Ruby, 23 bytes ```ruby ->n,x{eval'xn{eval'$<<$1;'n} ``` Try this online!
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4 months ago
Edit Post #285622 Initial revision 4 months ago
Answer A: Coat of Many Colours
Ruby, 101 79 76 72 bytes This challenge was one of the funniest I have ever solved! 72 bytes solution (I show the solution as a Ruby string - because binary data is filtered out) ```ruby "->l{l.sortby{'d\v\x162\x82\r\x1D\nJ\"\x01T\x0E?\x8B.\x11\x05\x06G(\fM\x00 HyI'.index''<<1[2,4].sum%145}...
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4 months ago
Edit Post #285621 Initial revision 4 months ago
Answer A: Repeat the characters
Ruby, 23 bytes ```ruby ->{1.gsub /./,'\0'2} ``` Try this online!
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4 months ago
Edit Post #285618 Initial revision 4 months ago
Answer A: Write a Deadfish Interpreter
Ruby, 70 67 66 bytes ```ruby ->c{a=0;c.bytes{|b|a,=[b<106?a+b/3-34:b<112?p(a):aa,0]-[-1,256]}} ``` Test this online!
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Edit Post #285611 Initial revision 4 months ago
Answer A: Small integer swapping
Ruby, 24 bytes ```ruby gets=/ /;puts$`,$'2+$` ``` Try this online!
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4 months ago
Edit Post #285610 Initial revision 4 months ago
Answer A: Word Count Tool
Ruby, 48 bytes ```ruby ->a{[a.split,b=a.chars-[$/],b-[' ']].map &:size} ``` Try this online!
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4 months ago
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4 months ago
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4 months ago
Edit Post #285606 Initial revision 4 months ago
Answer A: Digit Sum Integer Sequence (working title)
Ruby, 36 bytes Infinite version: ```ruby n=1;0while n+=p(n).digits.minmax.sum ``` Try this online! (program is interrupted after it reaches the 128KiB limit of output)
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4 months ago
Edit Post #285605 Initial revision 4 months ago
Answer A: Diagonalized alphabet
Ruby, 52 51 bytes 13.times{puts:YWUSQOMKIGECABDFHJLNPRTVXZ[12-1,14]} Attempt This Online!
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4 months ago
Edit Post #285597 Initial revision 4 months ago
Answer A: Word Set Square
Ruby, 70 bytes ```ruby ->s{s+=s.reverse;s[..-2].gsub(/./){t=$&+' '$.+$/;t[-2]=$&;$.+=1;t}+s} ``` Try this online!
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4 months ago
Edit Post #285592 Post edited:
4 months ago
Comment Post #283012 According to the description, input is a given as a string, not a array of strings (lines) as your solution is implemented.
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4 months ago
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4 months ago
Edit Post #285593 Initial revision 4 months ago
Answer A: Multiply complex numbers.
Ruby, 25 bytes ```ruby ->e{e.toce[/ ./].toc} ``` Try this online!
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4 months ago
Edit Post #285592 Post edited:
4 months ago
Edit Post #285592 Initial revision 4 months ago
Answer A: Cumulative Counts
Ruby, 31 bytes ```ruby ->a{a.map{$[1]=1.+$[1]||0}} ``` Try this online! `$` is a global variable, so calling this lambda multiple times (in a single process) would give wrong result. A 33 bytes version that does not rely on a global state: ```ruby ->a,c{a.map{c[1]=1.+c[1]||0}} ``` ...
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4 months ago
Edit Post #285588 Initial revision 4 months ago
Answer A: Bytes to Segfault
Ruby, 14 bytes ```ruby `kill -11 #$$` ``` Try this online!
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4 months ago
Edit Post #285519 Initial revision 4 months ago
Answer A: Generalized Sort
Ruby, 25 bytes Credits goes to @Shaggy and his JavaScript solution. ```ruby ->a,l{l.map{a.sort! &1}} ``` Try this online! The other solution which not mutate original array
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4 months ago
Edit Post #285512 Initial revision 4 months ago
Answer A: Reduce over the range [1..n]
Ruby, 22 bytes ```ruby ->{(1..2).reduce &1} ``` Try this online! Without using `reduce` (28 bytes): ```ruby f=->g,n{n<2?n:g[n,f[g,n-1]]} ``` Try this online!
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4 months ago
Comment Post #283278 Also, the solution you provided does not follow problem description. The code does not reduce 1..n (n is a parameter).
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4 months ago
Comment Post #283278 I don't think that first code is correct. If you want to pass proc/lambda as a block to `reduce` method, then `&` is needed. ```ruby ->{_2.reduce(&_1)} ``` To make it shorter, `()` can be omitted: ```ruby ->{_2.reduce &_1} ``` [Try this online](https://ato.pxeger.com/run?1=m72kqDSpcsH...
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4 months ago
Edit Post #285507 Post edited:
4 months ago
Edit Post #285507 Initial revision 4 months ago
Answer A: Golf golf challenge
Ruby, 100 96 bytes According to the rules, trailing white spaces and line feed are allowed and my program uses that: ```ruby ->p,s{"Par Bogey Double bogey Triple bogey Hole in one Albatross Eagle Birdie".lines[s<2?4:s-p]} ``` Try this online!
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4 months ago
Edit Post #285496 Initial revision 4 months ago
Answer A: Roll n fair dice
Ruby, 27 24 bytes -&gt;n,m{eval&#39;-rand(m)&#39;n} Attempt This Online! If we change the order of `n, m` parameters to `m, n` then following 23 bytes version work, but only in ruby 2.7 (it does not work in 3.x - bug or feature?): ```ruby ->{eval'-rand(1)'2} ```
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Edit Post #285482 Initial revision 4 months ago
Answer A: Evaluate a single variable polynomial equation
Ruby, 29 bytes ```ruby ->l,x{a,b=l;a ?a+xf[b,x]:0} ``` Try it online
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4 months ago
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4 months ago
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4 months ago
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4 months ago
Edit Post #285480 Initial revision 4 months ago
Answer A: Determine whether an integer is square-free
Ruby, 27 bytes ```ruby ->n{(2..n).all?{n%12>0}} ``` Try it online
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4 months ago
Comment Post #285404 @#53310 Good catch, thanks!
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4 months ago
Comment Post #285331 ```ruby ->a,b,c{%w[+ - * / % **].select{eval"a#{_1}b==c"}} ```
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5 months ago
Comment Post #285404 You can make it 1b shorter by using `$><<` to output value in P2: ``` puts"$><<#{gets}+gets.to_i" ```
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5 months ago