Permutation Sequence

Permutation Sequence

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 k^th permutation sequence.

解题思路，采用标准库的next_premutation（）进行枚举到第K个排列。

 

Code:

string getPermutation(int n,int k){

    string(n,'0');

    for(int i=0;i<n;i++){

        s[i]+=i+1;

    }

    for(int i=0;i<k-1;++i){

        next_permutation(s.begin(),s.end());

    }

    return s;

}