【笔试/面试】—— 序列全排列（递归版）

void perm(int seq[], int k, int m)
{
    if (k == m)
    {
        copy(seq, seq+m, ostream_iterator<int>(cout, " "));
        cout << endl;
        return;
    }
    for (int i = k; i < m; ++i)
    {
        swap(&seq[i], &seq[k]);
        perm(seq, k+1, m);
        swap(&seq[i], &seq[k]);
    }
}