poj 1050 最大子矩阵

import java.util.Arrays;
import java.util.Scanner;

public class Main{

public static void main(String []args){
Scanner cin = new Scanner(System.in);
int [][] matrix = new int [105][105];
int [] map = new int [105];
int n,i,j,k;
int max;

n = cin.nextInt();
for(i = 1; i <= n; i ++)
for(j = 1; j <= n; j ++)
matrix[i][j] = cin.nextInt();

max = -100000000;
int sum;

for(i = 1; i <= n; i ++)
{
Arrays.fill(map,0);
for(j = i; j <= n; j ++)
{
for(k = 1,sum = 0; k <= n; k ++)
{
map[k] += matrix[j][k];
sum = sum + map[k] > 0 ? sum + map[k]:0;
if(sum > max) max = sum;
}
}
}

System.out.println(max);
}
}