hdu 1166 敌兵布阵(线段树单点更新)

题意：单点更新线段树，求区间和。

线段树：http://blog.csdn.net/metalseed/article/details/8039326

#include<cstring>
#include<iostream>

#define M 50005
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
/*left,right,root,middle*/

int sum[M<<2];

inline void PushPlus(int rt)
{
	sum[rt] = sum[rt<<1] + sum[rt<<1|1];
}

void Build(int l, int r, int rt)
{
	if(l == r)
	{
		scanf("%d", &sum[rt]);
		return ;
	}
	int m = ( l + r )>>1;

	Build(lson);
	Build(rson);
	PushPlus(rt);
}

void Updata(int p, int add, int l, int r, int rt)
{

	if( l == r )
	{
		sum[rt] += add;
		return ;
	}
	int m = ( l + r ) >> 1;
	if(p <= m)
		Updata(p, add, lson);
	else
		Updata(p, add, rson);

	PushPlus(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 ) >> 1;
	int ans=0;
	if(L<=m )
		ans+=Query(L,R,lson);
	if(R>m)
		ans+=Query(L,R,rson);

	return ans;
}
int main()
{	
	int T, n, a, b;
	scanf("%d",&T);
	for( int i = 1; i <= T; ++i )
	{
		printf("Case %d:\n",i);
		scanf("%d",&n);
		Build(1,n,1);

		char op[10];

		while( scanf("%s",op) &&op[0]!='E' )
		{

			scanf("%d %d", &a, &b);
			if(op[0] == 'Q')
				printf("%d\n",Query(a,b,1,n,1));
			else if(op[0] == 'S')
				Updata(a,-b,1,n,1);
			else
				Updata(a,b,1,n,1);

		}
	}
	return 0;
}