线段树 ： hdu 1166 示例 [ 单点更新 ]

#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <cmath>
#include <vector>
#include <stack>
#include <deque>
#include <queue>
#include <bitset>
#include <list>
#include <map>
#include <set>
#include <iterator>
#include <algorithm>
#include <functional>
#include <utility>
#include <sstream>
#include <climits>
#include <cassert>
#define BUG puts("here!!!");
#define mid(x) (x) >> 1
using namespace std;
const int N = 50005;
struct Node {
	int a, b;
	int sum;
}t[3*N];
int SUM = 0;
int r[N];
void makeTree(int x, int y, int num) {
	t[num].a = x;
	t[num].b = y;
	if(x == y) t[num].sum = r[y];
	else {
	    int m = mid(x+y);
		makeTree(x, m, 2*num);
		makeTree(m+1, y, 2*num+1);
		t[num].sum = t[2*num].sum + t[2*num+1].sum;
	}
}
void add(int x, int ren, int num) {
	t[num].sum += ren;
	if(x == t[num].a && x == t[num].b) return;
	if(x <= mid(t[num].a + t[num].b)) {
		add(x, ren, 2*num);
	}
	else add(x, ren, 2*num+1);
}
void query(int x, int y, int num) {
	if(x <= t[num].a && t[num].b <= y) { // 找终止
		SUM += t[num].sum;
	}
	else {
        int m = mid(t[num].a + t[num].b);
        if(x <= m) query(x, y, 2*num);
        if(y > m) query(x, y, 2*num+1);
	}
}
int main() {
	int e = 0, T, n;
	cin >> T;
	while(T--) {
		memset(r, 0, sizeof(r));
		memset(t, 0, sizeof(t));
		cout << "Case " << ++e << ':' << endl;
		cin >> n;
		for(int i = 1; i <= n; i++) {
			scanf("%d", r+i);
		}
		makeTree(1, n, 1);
		char str[10];
		int a, b;
		while(scanf("%s", str)) {
			if(str[0] == 'E') {
				break;
			}
			else if(str[0] == 'A') {
				scanf("%d%d", &a, &b);
				add(a, b, 1);
			}
			else if(str[0] == 'S') {
				scanf("%d%d", &a, &b);
				add(a, (-b), 1);
			}
			else if(str[0] == 'Q') {
				scanf("%d%d", &a, &b);
				SUM = 0;
				query(a, b, 1);
				printf("%d\n", SUM);
			}
		}
	}
	return 0;
}