hdu1166 树状数组

不知道为什么用C++输入输出死活不过，换成C的就过了。。。
#include <stdio.h>
#include <string.h>

//==============================
#define maxn 50020

int c[maxn];
int a[maxn];
int n;
int t;

int lowbit(int x)
{
    return x&(-x);
}

int Sum(int n)
{
    int sum = 0;
    while(n>0)
    {
        sum += c[n];
        n = n - lowbit(n);
    }
    return sum;
}

void update(int i,int x)
{
    while(i <= n)
    {
        c[i] = c[i] + x;
        i = i + lowbit(i);
    }
}

int GetSum(int x1,int x2)
{
    return Sum(x2) - Sum(x1-1);
}

//===================================
int main()
{
    scanf("%d",&t);
    int count = 0;
    while(t--)
    {
        count++;
        memset(a,0,sizeof(a));
        memset(c,0,sizeof(c));
        scanf("%d",&n);
        for(int i = 1; i <= n; i++)
        {
            scanf("%d",&a[i]);
            update(i,a[i]);
        }
        //cout<<"case "<<count<<":"<<endl;
        printf("Case %d:\n",count);
        char oper[11];
        int i,j;
        while(scanf("%s",oper)==1)
        {
            if(strcmp(oper,"End")==0)
                break;
            scanf("%d%d",&i,&j);
            if(strcmp(oper,"Query")==0)
            {
                printf("%d\n",GetSum(i,j));
            }
            if(strcmp(oper,"Add")==0)
            {
                a[i] += j;
                update(i,j);
            }
            if(strcmp(oper,"Sub")==0)
            {
                a[i] -= j;
                update(i,-j);
            }
        }
    }
    return 0;
}