poj 2029 && zoj 1716 Get Many Persimmon Trees

#include<stdio.h>
#include<iostream>
#include<string.h>
using namespace std;
#define N 130
int c

;
int n,m;
int lowbit(int x)
{
return x&(-x);
}
void Updata(int x,int y)
{
for(int i=x;i<=N;i+=lowbit(i))
{
for(int j=y;j<=N;j+=lowbit(j))
{
c[i][j]++;
}
}
}
int Getsum(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+=c[i][j];
}
}
return sum;
}
int main()
{
int cnt;
int x,y,x1,y1;
while(scanf("%d",&cnt)&&cnt)
{
scanf("%d%d",&n,&m);
memset(c,0,sizeof(c));
while(cnt--)
{
scanf("%d%d",&x,&y);
Updata(x,y);
}
scanf("%d%d",&x1,&y1);
int max=0;
for(int i=x1;i<=n;i++)
{
for(int j=y1;j<=m;j++)
{
int ans=Getsum(i,j)-Getsum(i-x1,j)-Getsum(i,j-y1)+Getsum(i-x1,j-y1);
if(max<ans)max=ans;
}
}
printf("%d\n",max);
}
return 0;
}