输入第一行包含两个整数m和n，即矩阵的行数和列数。之后m行，每行n个整数，描述整个矩阵。程序最终输出最大的子矩阵和。（最后一空4分，其余3分，共16分）
#include <stdio.h>
const int SIZE = 100;
int matrix[SIZE + 1][SIZE + 1];
int rowsum[SIZE + 1][SIZE + 1]; //rowsum[i][j]记录第i行前j个数的和 int m, n, i, j, first, last, area, ans;
int main( ) {
scanf("%d %d", &m, &n);
for (i = 1; i <= m; i++)
for (j = 1; j <= n; j++)
scanf("%d", &matrix[i][j]);
ans = matrix1
for (i = 1; i <= m; i++) 2
for (i = 1; i <= m; i++)
for (j = 1; j <= n; j++)
rowsum[i][j] = 3
for (first = 1; first <= n; first++)
for (last = first; last <= n; last++) {
4
for (i = 1; i <= m; i++) {
area += 5
if (area > ans) ans = area;
if (area < 0) area = 0;
}
}
printf("%d\n", ans);
return 0;
} 
