uva-10827

　　题意：还是寻找子数组和最大，只是上下左右可以联通了，NxN,变成2Nx2N就行了，循环了四层，D_Double用了三层，有个大佬用dp是俩层

#include <string>
#include<iostream>
#include<map>
#include<memory.h>
#include<vector>
#include<algorithm>
#include<queue>
#include<vector>
#include<stack>
#include<math.h>
#include<iomanip>
#include<bitset>
#include"math.h"
namespace cc
{
    using std::cout;
    using std::endl;
    using std::cin;
    using std::map;
    using std::vector;
    using std::string;
    using std::sort;
    using std::priority_queue;
    using std::greater;
    using std::vector;
    using std::swap;
    using std::stack;
    using std::queue;
    using std::bitset;


    constexpr int N = 80;
    int a[N * 2][N * 2]; 

    void solve()
    {
        int n;
        cin >> n;
        while (n--)
        {
            int R;
            cin >> R;
            memset(a, 0, sizeof(a));
            for (int i = 1;i <= R;i++)
            {
                for (int j = 1;j <= R;j++)
                {
                    cin >> a[i][j];
                    a[i][R + j] = a[i][j];
                    a[R + i][j] = a[i][j];
                    a[R + i][R + j] = a[i][R + j];
                }
            }
            for (int i = 1;i <= 2*R;i++)
            {
                for (int j = 1;j <= 2*R;j++)
                {
                    a[i][j] = a[i][j] + a[i - 1][j];
                }

            }
            int max = INT32_MIN;
            for (int i = 0;i <= R;i++)
            {
                for (int j = i + 1;j <= i + R;j++)
                {
                    for (int k = 1;k <= R;k++)
                    {
                        int sum = 0;
                        for (int c = k;c < k + R;c++)
                        {
                            if (sum < 0)
                                sum = 0;
                            else
                                sum = sum + a[j][c] - a[i][c];
                            if (sum > max) 
                            {
                                max = sum;
                            }
                        }
                    }
                }
            }
            cout << max << endl;


        }


    }
};
 

int main()
{

#ifndef ONLINE_JUDGE
    freopen("d://1.text", "r", stdin);
#endif // !ONLINE_JUDGE
    cc::solve();



    return 0;
}