Heavily based on this closed challenge from SE.

Description

A Sumac sequence starts with two non-zero integers $t_1$ and $t_2.$

The next term, $t_3 = t_1 - t_2$

More generally, $t_n = t_{n-2} - t_{n-1}$

The sequence ends when $t_n ≤ 0$. All values in the sequence must be positive.

Challenge

Given two integers $t_1$ and $t_2$, compute the Sumac sequence, and output it's length.

If there is a negative number in the input, remove everything after it, and compute the length.

You may take the input in any way (Array, two numbers, etc.)

Test Cases

(Sequence is included for clarification)

[t1,t2]   Sequence          n
------------------------------
[120,71]  [120,71,49,22,27] 5
[101,42]  [101,42,59]       3
[500,499] [500,499,1,498]   4
[387,1]   [387,1,386]       3
[3,-128]  [3]               1
[-2,3]    []                0
[3,2]     [3,2,1,1]         4

Scoring

This is code-golf. Shortest answer in each language wins.

posted about 4 years ago

CC BY-SA 4.0

3y ago by General Sebast1an‭

Razetime‭

2870 reputation 42 65 322 83