2014年的题目，给定n个元素，打印出全排列

比如输入1 2 3，打印出6种排列情况

include 
     
       using namespace std;void swap(int& a, int& b) {  int t = a;  a = b;  b = t;}void perm(int* array, int n, int k) {  if (k == n) 　{    for (int i = 0; i < n; i++) 　　{      cout << array[i] << " ";    }    cout << endl;  }  for (int i = k; i