import java.util.*;
public class Tarray {
static Scanner scanner = new Scanner(System.in);
public static void main(String args[]){
int m,n;
int b;
Scanner scanner = new Scanner(System.in);
System.out.println("二维数组的列数： ");
m = scanner.nextInt();
System.out.println("二维数组的行数：");
n = scanner.nextInt();
int arr[][] = new int[n][m];
System.out.println("请输入二位数组：");
for(int i = 0;i<n;i++)
for(int j=0;j<m;j++)
{
arr[i][j] = scanner.nextInt();
}
System.out.println(" ");
b = maxArrSum(arr);
System.out.println("最大联通数组的最大和为"+b);
}
public static int[][] arrSum(int arr[][]){
int m = arr.length;
int n = arr[0].length;
int p[][] = new int[m+1][n+1];
p[0][0] = arr[0][0];
for(int i=0; i<=m; i++) p[i][0] = 0;
for(int i=0; i<=n; i++) p[0][i] = 0;
for(int i=1; i<=m; i++){
for(int j=1; j<=n; j++){
p[i][j] = p[i-1][j] + p[i][j-1] + arr[i-1][j-1] - p[i-1][j-1];
}
}
return p;
}
//遍历所有二维数组的矩形区域
static int maxArrSum(int arr[][]){
int m = arr.length;
int n = arr[0].length;
int p[][] = arrSum(arr);
int ans = Integer.MIN_VALUE;
for(int i=1; i<=m; i++){
for(int j=1; j<=n; j++){
for(int endi=i; endi <=m; endi++){
for(int endj=j; endj<=n; endj++){
int sum = p[endi][endj] - p[i-1][endj] - p[endi][j-1] + p[i-1][j-1];
if(ans < sum) ans = sum;
}
}
}
}
return ans;
}
}