全排列

# include <iostream>
# include <cstdio>
using namespace std;
void perm(int list[], int k, int m)
{
    int i;
    if(k > m)
    {
        for(i = 0; i <= m; i++)
            printf("%d ", list[i]);
        printf("\n");
    }
    else
    {
        for(i = k; i <= m; i++)
        {
            swap(list[k], list[i]);
            perm(list, k + 1, m);
            swap(list[k], list[i]);
        }
    }
}
int main()
{
    int list[] = {1, 2, 3, 4};
    perm(list, 0, 3);
    return 0;
}