I am trying to solve Educational Round 115 Problem C by storing number of occurrences in the map. My submission works with MSVC https://mirror.codeforces.com/contest/1598/submission/133072945 but doesn't work with GCC https://mirror.codeforces.com/contest/1598/submission/133071532. I can't repro it locally so I can't debug it but adding check for non-existing values https://mirror.codeforces.com/contest/1598/submission/133073553 fixes the problem.

So it looks like that for missing integer values operator[] for unordered_map instead of returning 0 (default initialized value), returns uninitialized value which looks really weird. Am I missing something here?