I am trying to reduce the calls to access map elements so used varaibles by reference but got runtime error. Can anyone help. Runs correctly on local machine.

https://mirror.codeforces.com/contest/1974/submission/262484871

Can anyone help me to figure out that why my solution for Atcoder' Problem C is running locally but giving wrong answer on Atcoder remote judge? (I have also not used any global variables).

Link to Problem: "https://atcoder.jp/contests/abc354/tasks/abc354_c"

Link to Solution: "https://cl1p.net/code_c"

Can anyone help me indentifying why my code is giving runtime error for this following code in Problem G: (https://mirror.codeforces.com/contest/1971/submission/260600724)

Edit: Got the issue and got AC but could not understand the reason