hdu 1166 敌兵布阵 （树状数组）

#include<stdio.h>
#include<string.h>
#define N 600000
int n;
int a[N],c[N];
int lowbit(int x)
{
    return x&(-x);
}
int sum(int k)
{
    int ans=0;
    while(k>0)
    {
        ans+=c[k];
        k=k-lowbit(k);
    }
    return ans;
}
int add(int pos ,int num)
{
    while(pos<=n)
    {
        c[pos]+=num;
        pos+=lowbit(pos);
    }
}
int main()
{
    int T,l,i;
    scanf("%d",&T);
    char str[10];
    for(l=1;l<=T;l++)
    {
        scanf("%d",&n);
        memset(c,0,sizeof(c));
        a[0]=0;
        for(i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
            add(i,a[i]);

        }
        printf("Case %d:\n",l);
        while(scanf("%s",str)!=EOF)
        {
            if(strcmp(str,"End")==0)break;
            if(strcmp(str,"Query")==0)
            {
                int x,y;
                scanf("%d%d",&x,&y);
                int t;
                if(x>y)
                {
                    t=x;x=y;y=t;
                }
                printf("%d\n",sum(y)-sum(x-1));
            }
            else
            {
                int pos,y;
                if(strcmp(str,"Add")==0)
                {
                    scanf("%d%d",&pos,&y);
                    add(pos,y);

                }
                else
                {
                     scanf("%d%d",&pos,&y);
                      add(pos,-y);

                }

            }
        }

    }
}