Can someone please tell me why my code fails on problem D of Atcoder Beginner Contest? Here is the link to my code: https://atcoder.jp/contests/abc043/submissions/10192786 and here is the link to the problem: https://atcoder.jp/contests/abc043/tasks/arc059_b .

My code works and gives correct output on my computer but not here on Codeforces. Can anyone tell me why? 1283C - Friends and Gifts 67832300