hdu 1166 赤裸裸的树状数组

题目没啥说的，赤裸裸的树状数组

/*
 * hdu1166/win.cpp
 * Created on: 2011-9-6
 * Author    : ben
 */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;

const int MAXN = 50100;
int N, M;
int array[MAXN];

inline int lowbit(int x) {
    return x & (x ^ (x - 1));
}

int sum(int n) {
    int ret = 0;
    for(int i = n; i > 0; i -= lowbit(i)) {
        ret += array[i];
    }
    return ret;
}

void update(int index, int value) {
    for (int i = index; i <= N; i += lowbit(i)) {
        array[i] += value;
    }
}

void work();
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    work();
    return 0;
}

void work() {
    char op[20];
    int a, b, T, temp;
    scanf("%d", &T);
    for (int t = 1; t <= T; t++) {
        printf("Case %d:\n", t);
        scanf("%d", &N);
        memset(array, 0, sizeof(array));
        for (int i = 1; i <= N; i++) {
            scanf("%d", &temp);
            update(i, temp);
        }
        while (scanf("%s", op) == 1) {
            if (strcmp(op, "End") == 0) {
                break;
            }
            scanf("%d%d", &a, &b);
            if (strcmp(op, "Query") == 0) {
                printf("%d\n", sum(b) - sum(a - 1));
            } else if (strcmp(op, "Add") == 0) {
                update(a, b);
            } else {
                update(a, -b);
            }
        }
    }
}