The set [1,2,3,…,n] contains a total of n! unique permutations.

By listing and labeling all of the permutations in order,

We get the following sequence (ie, for n = 3):

1. "123"
2. "132"
3. "213"
4. "231"
5. "312"
6. "321"

 

Given n and k, return the kth permutation sequence.

Note: Given n will be between 1 and 9 inclusive.

 

参考：http://www.cnblogs.com/tenosdoit/p/3721918.html

 

C++实现代码：

#include
     
      #include
      
       #include
       
        using namespace std;class Solution {public:    string getPermutation(int n, int k) {        if(n==0)            return "";        int total=factorial(n);        string str=string("123456789").substr(0,n);        string ret(n,' ');        int i;        for(i=0;i