I was solving 1955G - GCD on a grid, and I made 2 submissions. The first one 262439330 which gave TLE. The second one 262487569 ran in just 765ms.

The only change I made in these 2 submissions is that I declared a vector isposs globally instead of declaring it again in the function isPoss. Does memory allocation in C++ really have such a large overhead, or is there any other reason? I mean it takes more than 4x time to run, which is unexpected to me.