I was trying to solve this problem

and calculating the GCD for two double variables i put eps = 1e-8 and i got WA

wondering what was going on i looked at other codes and all they did that was different was put eps = 1e-4

i tried it and got AC, and tried every value upto 1e-8 and all of them got right answers

it got me wondering about the reason

here is my submission

any clarification would be appreciated