参考:http://acm.hdu.edu.cn/showproblem.php?pid=1081
#include<stdio.h>
#include<limits.h>
#include<string.h>
#define NUM 110
int get_max(int x,int y)
{
return x>y?x:y;
}
int
main(void)
{
int N;
int list[NUM][NUM];
while(scanf("%d",&N) != EOF)
{
int ans = INT_MIN;
memset(list,0,sizeof(list));
int i,j,k;
for(i = 1;i<=N;i++)
for(j = 1;j<=N;j++)
scanf("%d",&list[i][j]);
for(i = 1;i<=N;i++)
{
for(j=1;j <= N;j++)
list[i][j] += list[i][j-1];
}
for(i = 1;i<=N;i++)
for(j = i;j<=N;j++)
{
int sum = 0;
for(k=1;k<=N;k++)
{
sum = get_max(sum+list[k][j] - list[k][i-1],list[k][j]-list[k][i-1]);
ans = get_max(ans,sum);
}
}
printf("%d\n",ans);
}
return 0;
}