HUST 1586 数字排列

#include <bits/stdc++.h>
using namespace std;
char a[10][10];
int b[10];
int main()
{
    int n, k;
    while(~scanf("%d %d", &n, &k))
    {
        int output = 0x3f3f3f3f;
        memset(a, 0, sizeof(a));
        memset(b, 0,  sizeof(b));
        for (int i = 1; i <= n; i++)
        {
            scanf("%s",&a[i]);
        }
        for (int i = 1; i <= k; i++)
        {
            b[i] = i;
        }
        int m = 1;
        for (int i = 1; i <= k; i++) //统计全排列个数，n!个
        {
            m *= i;
        }
        for (int i = 0; i <= m; i++)
        {
            next_permutation(b + 1, b + 1 + k);
            int c[10];
            memset(c, 0, sizeof(c));
            for (int i = 1; i <= n; i++)
            {
                for (int j = 1; j <= k; j++)
                {
                    c[i] = c[i] * 10 + a[i][b[j] - 1] - ‘0‘; // a[i]数组输入的时候是从0开始的
                } //用C数组来存储a的数值
            }
            sort(c + 1, c + n + 1);
            
            output = min(output, c[n] - c[1]);
        }
        cout << output << endl;
    }
    

    return 0;
}