In this problem, I have used a comparator function named "checking", for this, it is giving runtime error. But if i use another comparator function named "checking2" then it gets accepted. But these two comparator function is almost same. Why is it giving runtime error for "checking" function? please help.
Problem Link: https://codeforces.net/contest/1846/problem/C
Accepted code with checking comparator: https://codeforces.net/contest/1846/submission/212708795
Runtime error code with cheking2 comparator: https://codeforces.net/contest/1846/submission/212720506
https://codeforces.net/blog/entry/70237
TL;DR: Comparators must return false when comparing equal elements. Your function
checkingdoes this,checking2doesn't.