Recently I've tried to solve this problem 160D - Edges in MST but there was a bug in my code, I've tried to debug the code but that was just wasting time, then I've rewritten the code again and got AC :D. Making a comparison between the two codes was so weird they were almost identical, I read about undefined - behavior in C++ but I couldn't find anything like that.

WA code: 12013993

AC code: 12013990

Any help would be appreciated.