树状数组入门 之 hdu 1166

//  [4/7/2014 Sjm]
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <string>
using namespace std;
const int MAX_N = 50000;
int bit[MAX_N + 1], n;

int mySum(int i)
{
int sum = 0;
while (i>0){
sum += bit[i];
i -= (i&(-i));
}
return sum;
}

void myAdd(int i, int x)
{
while (i<=n) {
bit[i] += x;
i += (i&(-i));
}
}

int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);
int T;
scanf("%d", &T);
for (int i = 1; i <= T; i++)
{
memset(bit, 0, sizeof(bit));
printf("Case %d:\n", i);
scanf("%d", &n);
for (int j = 1; j <= n; j++) {
int x;
scanf("%d", &x);
myAdd(j, x);
}
string str;
while (cin>>str && ('E' != str[0]))
{
int a, b;
scanf("%d %d", &a, &b);
if ('Q' == str[0])
printf("%d\n", mySum(b) - mySum(a-1));
else {
if ('A' == str[0]) myAdd(a, b);
else myAdd(a, -b);
}
}
}
return 0;
}