In the problem B, round #763(Div 2) is submitted the following code during the contest: Incorrect Submission: [https://mirror.codeforces.com/contest/1623/submission/140919117] It resulted in "Runtime error on Test 8" after System Testing, later after the contest, I resubmitted after just a minor variation. Correct Solution: [https://mirror.codeforces.com/contest/1623/submission/140962533 The only difference between the two codes is the comparator function just declared above int main(), called psort. In the one giving Runtime error, it has a "<=" comparator, and in the correct one it has "<" comparator. Could anyone please tell the difference.