健壮白猫
Codeforces - 1463C. Busy Robot （思维）Busy Robot
功能:①快速求前缀和O(logn)O(logn)O(logn)②修改某一个数O(logn)O(logn)O(logn)操作：①：建树void add(int x, int c) { //树状数组的插入操作 for (int i = x;i <= n;i += lowbit(i))tr[i] += c;}②：区间查询：1 ~ x 前缀和for(int i = x;i <= n;i += lowbit(i))res += c;③：单点修改：for(int i = x;i;
