树状数组 区间和

#include<cstdio>  // 求区间和 
#include<cstring>
#define lowerBit(x) (x&(-x))
int num[10000];
int n;
void UpDate(int x,int y) //把第x个数加y
{
while (x <= n)
{
num[x] += y;
x = x+lowerBit(x);
}
}
int Query(int x) //求从1到x的和 
{
int sum = 0;
while (x > 0)
{
sum += num[x];
x = x-lowerBit(x);//x&(x-1)
}
return sum;
}
int main()
{
scanf ("%d",&n);
memset(num,0,sizeof(num));
for (int i = 1 ; i <= n ; i++)
{
int t;
scanf ("%d",&t);
UpDate(i,t);
}

int m;
scanf ("%d",&m);
while (m--)
{
int x,y;
scanf ("%d %d",&x,&y);
printf ("%d\n",Query(y)-Query(x-1));
}
return 0;
}