HDU ACM 1166 敌兵布阵(树状数组)

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

 

#include <iostream>
#include <string>
using namespace std;
const int MAX = 50000 + 10;
int C[MAX];
int n;
int LowBit(int x)
{
    return (x&(-x));
}
void Update(int num,int k)
{
    while(num <= n)
    {
        C[num] += k;
        num += LowBit(num);
    }
}
int CalSum(int num)
{
    int sum = 0;
    while(num > 0)
    {
        sum += C[num];
        num -= LowBit(num);
    }
    return sum;
}
void Calculate(int i,int j)
{
    cout<<CalSum(j) - CalSum(i-1)<<endl;
}
int main()
{
    int Case = 0;
    int T;
    cin>>T;
    while(T--)
    {
        Case++;
        cout<<"Case "<<Case<<":"<<endl;
        memset(C,0,sizeof(C));
        scanf("%d",&n);
        int A[MAX];
        int i;
        for(i=1;i<=n;i++)
        {
            scanf("%d",&A[i]);
            Update(i,A[i]);
        }
        string str;
        while(cin>>str)
        {
            int a,b;
            if(str == "End")
            {
                break;
            }
            if(str == "Query")
            {
                scanf("%d%d",&a,&b);
                Calculate(a,b);
            }
            if(str == "Add")
            {
                scanf("%d%d",&a,&b);
                Update(a,b);
            }
            if(str == "Sub")
            {
                scanf("%d%d",&a,&b);
                Update(a,(-b));
            }
        }
    }
    return 0;
}