poj_1195Mobile phones,二维树状数组

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int a[1300][1300];
int s;
int lowbit(int x)
{
return x&(-x);
}
void add(int x,int y,int d)
{
for(int i=x;i<=s;i+=lowbit(i))
for(int j=y;j<=s;j+=lowbit(j))
a[i][j]+=d;
}
int sum(int x,int y)
{
int ret=0;
for(int i=x;i>0;i-=lowbit(i))
for(int j=y;j>0;j-=lowbit(j))
ret+=a[i][j];
return ret;
}
int main()
{
while(scanf("%d%d",&s,&s)!=EOF)
{
memset(a,0,sizeof(a));
int n,x,y,d,xt,yt;
while(scanf("%d",&n))
{
if(n==3) break;
if(n==1)
{
scanf("%d%d%d",&x,&y,&d);
x++,y++;
add(x,y,d);
}
if(n==2)
{
scanf("%d%d%d%d",&x,&y,&xt,&yt);
x++,y++,xt++,yt++;
int ans=sum(xt,yt)-sum(xt,y-1)-sum(x-1,yt)+sum(x-1,y-1);
cout<<ans<<endl;
}
}
}
return 0;
}