软件工程概论---环状二维数组最大子数组和

#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 <=2* col-1; j++)
        {
            for (j = 1; j <= col; j++)
            {
                cin >> A[i][j];
            }
            for (j = col + 1; j <= 2 * col - 1; j++)
            {
                A[i][j] = A[i][j-col];
            }
        }
    }
    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 <= 2*col-1; 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 <=2* col-1; j++)
        {
            maxendinghere = max(MatrixSum(n1, j, n2, j), MatrixSum(n1, j, n2, j) + maxendinghere);
            maxsofar = max(maxendinghere, maxsofar);
        }
    }
    cout << maxsofar;
}