While solving this problem from CSES — Hamming Distance — I was surprised to see that my O(N^2) solution passed where N = 2e4. The solution wasn't pruned so I'm sure it must've taken ~ N^2 operations.

What exactly is a good estimate on number of operations allowed? I believed 3e7 operations was a good estimate, but clearly this isn't the case, so what is the actual threshold?