CF竞赛题目讲解_CF1354D(树状数组)

https://codeforces.com/problemset/problem/1354/d

• if  1≤ki≤n, then the i-th query is "insert ki into the multiset";

• if ki<0, then the i-th query is "remove the |ki|-th order statistics from the multiset". For this query, it is guaranteed that |ki| is not greater than the size of the multiset.

在这个程序里面，使用树状数组统计数据个数。