Leetcode 59 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 kth permutation sequence.

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

Thinking, using the lexicographic method, and http://blog.csdn.net/mlweixiao/article/details/38897499

public class Solution {private void nextPermutation(int[] num) {int i;int cur = -1;int temp;// find the last increase sequencefor (i = num.length - 1; i >= 1; i--) {if (num[i] > num[i - 1]) {cur = i - 1;break;}}// if the increase sequence exists,// swap the cur and the last one(bigger than it)if (cur != -1) {for (i = num.length - 1; i > cur; i--) {if (num[i] > num[cur]) {temp = num[cur];num[cur] = num[i];num[i] = temp;break;}}}for (i = cur + 1; 2 * i <= cur + num.length - 1; i++) {temp = num[i];num[i] = num[num.length - i + cur];num[num.length - i + cur] = temp;}}    public String getPermutation(int n, int k) {        int [] temp=new int[n];        StringBuffer s=new StringBuffer("");                for(int i=0;i<n;i++){        temp[i]=i+1;        }        for(int i=1;i<k;i++){        nextPermutation(temp);        }                for(int i=0;i<n;i++){        s.append(temp[i]);        }        return s.toString();    }}

Leetcode 59 permutation sequence