HDU1166树状数组

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#include<iostream>
#include<cstdio>
#include<cstring> 
const int maxn=50000+10;
using namespace std;
int c[maxn],n;
int lowbit(int x){return x & -x;}
void add(int x,int y){
	while(x<=n){
		c[x]+=y;
		x+=lowbit(x);
	}
}
int cal(int x){
	int sum=0;
	while(x){
		sum+=c[x];
		x-=lowbit(x);
	}
	return sum;
}
int main(){
	int i,j,k,m,L,R,t;  
    char op[10];  
    scanf("%d",&t);  
    for(int cas=1;cas<=t;cas++){  
    	memset(c,0,sizeof(c));
        scanf("%d",&n);          
        for(i=1;i<=n;i++){
			scanf("%d",&k);
			add(i,k);
		}
        printf("Case %d:\n",cas);  
        while(scanf("%s",op),op[0]!='E'){  
            scanf("%d%d",&L,&R);  
            if(op[0]=='Q')  
                printf("%d\n",cal(R)-cal(L-1));
            else if(op[0]=='A')  
                add(L,R);
            else  
                add(L,-R);
        }  
    }  
	return 0;
}