I was solving the Planets Queries I problem in CSES (a standard binary lifting problem).

After getting a few TLE on one of the test cases, I finally got AC, but it took 1.00 seconds to pass that test case, which is way too close. On checking other submissions with exact same logic, and investigating a bit more, I changed vector<vector> declaration in my code to static int array declaration, and my code, with everything being exact same, worked in 0.60 seconds. Usually there shouldn't be such a drastic difference. While solving codeforces problem, I have observed that vectors and static array take the same time, and sometimes vectors are faster.

Can anyone explain the reason behind this? Thanks.

Submission using vector<vector> : https://cses.fi/paste/7d2b7a0b66df52a2ea28b6/ Submission using static int array : https://cses.fi/paste/6d8b9ef1a192caa1ea28f1/