HDU 1166 敌兵布阵

地址:http://acm.hdu.edu.cn/showproblem.php?pid=1166

代码:

/**
*  题意:对长度为N的数组,进行修改元素值,和查询[a,b]区间值的操作
*  解题思路:线段树模板题
*/
#include <stdio.h>
#define lson l , m , rt*2
#define rson m + 1 , r , rt*2+1
const int maxn = 55555;
int sum[maxn * 4];
void PushUP(int rt) 
{
	sum[rt] = sum[rt * 2] + sum[rt * 2 + 1]; 
}
void build(int l, int r, int rt)
{
	if (l == r)
	{
		scanf("%d", &sum[rt]);
		return;
	}
	int m = (l + r) / 2;
	build(lson);
	build(rson);
	PushUP(rt);
}
void update(int p, int add, int l, int r, int rt)
{
	if (l == r)
	{
		sum[rt] += add;
		return;
	}
	int m = (l + r) / 2;
	if (p <= m)
		update(p, add, lson);
	else
		update(p, add, rson);
	PushUP(rt);
}
int query(int L, int R, int l, int r, int rt)
{
	if (L <= l && r <= R)
	{
		return sum[rt];
	}
	int m = (l + r) / 2;
	int ret = 0;
	if (L <= m)
		ret += query(L, R, lson);
	if (R > m)
		ret += query(L, R, rson);
	return ret;
}
int main()
{
	int T, n;
	scanf("%d", &T);
	for (int cas = 1; cas <= T; cas++)
	{
		printf("Case %d:\n", cas);
		scanf("%d", &n);
		build(1, n, 1);
		char op[10];
		while (scanf("%s", op))
		{
			if (op[0] == 'E') break;
			int a, b;
			scanf("%d%d", &a, &b);
			if (op[0] == 'Q')
				printf("%d\n", query(a, b, 1, n, 1));
			else if (op[0] == 'S')
				update(a, -b, 1, n, 1);
			else
				update(a, b, 1, n, 1);
		}
	}
	return 0;
}


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