poj 1195 Mobile phones

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int tree[1300][1300];
int s;
inline int lowbit(int x)
{
return x&(-x);
}
void add(int x,int y,int c)
{
for(int i=x;i<=s;i+=lowbit(i))
for(int j=y;j<=s;j+=lowbit(j))
tree[i][j]+=c;
}
int query(int x,int y)
{
int sum=0;
for(int i=x;i>0;i-=lowbit(i))
for(int j=y;j>0;j-=lowbit(j))
sum+=tree[i][j];
return sum;
}
int main()
{
while(1)
{
int k;
scanf("%d",&k);
if(k==3)break;
switch(k)
{
case 0: {
scanf("%d",&s);
memset(tree,0,sizeof(tree));
break;
}
case 1:
{
int x,y;int a;
scanf("%d%d%d",&x,&y,&a);
x++;y++;
add(x,y,a);break;
}
case 2: {
int x1,y1,x2,y2;
scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
x1++;y1++;x2++;y2++;
int ans=query(x2,y2)-query(x2,y1-1)-query(x1-1,y2)+query(x1-1,y1-1);
printf("%d\n",ans);
break;
}
default:break;
}

}

return 0;
}