You are tiling a rectangular floor that is width by height centimetres using identical square tiles, with no cutting and no gaps. Write tile_size(width, height) that returns the side length of the largest square tile that works.
Examples
Input: width = 12, height = 18
Output: 6
Explanation: 6 cm tiles fit exactly (2 by 3). 12 cm tiles would not fit the 18 cm side.
Input: width = 7, height = 5
Output: 1
Constraints
1 <= width, height <= 10**9
Goals
- Recognise a gcd problem in disguise
- Implement Euclid's algorithm with a loop