二维数组最大值

#include <iostream>
#include<time.h>
using namespace std;
#define max(a,b) ((a)>(b)?(a):(b))
#define MAXN 100

int A[MAXN][MAXN];
int PartSum[MAXN][MAXN];

//计算子矩阵的和
int MatrixSum(int s, int t, int i, int j)
{
	return PartSum[i][j] - PartSum[i][t - 1] - PartSum[s - 1][j] + PartSum[s - 1][t - 1];
}

int main()
{
	srand((unsigned)time(NULL));
	int row, col, i, j;
	cout << "请输入二维数组的行数和列数:";
	cin >> row >> col;
	for (i = 1; i <=row; i++)
	{
		for (j = 1; j <=col; j++)
		{
			A[i][j] = rand() % 20 - 10;
			cout << A[i][j] << " ";
		}
		cout << endl;
	}
	for (i = 0; i <= row; i++)
		PartSum[i][0] = 0;
	for (j = 0; j <= col; j++)
		PartSum[0][j] = 0;
	// 计算矩阵的部分和
	for (i = 1; i <= row; i++)
	for (j = 1; j <= col; j++)
		PartSum[i][j] = A[i][j] + PartSum[i - 1][j] + PartSum[i][j - 1] - PartSum[i - 1][j - 1];
	int n1, n2;
	int maxsofar = A[1][1];
	for (n1 = 1; n1 <= row; n1++)
	for (n2 = n1; n2 <= row; n2++)
	{
		// 将子矩阵上下边界设为第n1行和第n2行，在这些子矩阵中取最大值,类似于一维数组求最大值
		int maxendinghere = MatrixSum(n1, 1, n2, 1);
		for (j = 2; j <= col; j++)
		{
			maxendinghere = max(MatrixSum(n1, j, n2, j), MatrixSum(n1, j, n2, j) + maxendinghere);
			maxsofar = max(maxendinghere, maxsofar);
		}
	}
	cout << maxsofar;
}