【未知】P2216 [HAOI2007]理想的正方形

#include<iostream>
using namespace std;

const int INF = 0x3f3f3f3f;

int a, b, n;
int g[1010][1010];
int maxn[1010][1010], minn[1010][1010];

int max(int a,int b)

{
    return a>b?a:b;

}

int min(int a,int b)

{
    return a<b?a:b;

}

int main()
{

    ios::sync_with_stdio(false);

    cin >> a >> b >> n;
    for (int i = 0; i < a; i++)
        for (int j = 0; j < b; j++)
        {
            cin >> g[i][j];

            maxn[i][j] = minn[i][j] = g[i][j];

        }

    for (int k = 2; k <= n; k++)
        for (int i = 0; i + 1 < a; i++)
            for (int j = 0; j + 1 < b; j++) 
            {
                maxn[i][j] = max(g[i][j], max(maxn[i + 1][j + 1], max(maxn[i + 1][j], maxn[i][j + 1])));
                minn[i][j] = min(g[i][j], min(minn[i + 1][j + 1], min(minn[i + 1][j], minn[i][j + 1])));
            }

    int minimum = INF;
    for (int i = 0; i <= a - n; i++)
        for (int j = 0; j <= b - n; j++)
             minimum = min(minimum, maxn[i][j] - minn[i][j]);

    cout << minimum;
}