public class Solution
extends Object
60 - Permutation Sequence\.
Hard
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 for `n = 3`:
1. `"123"`
2. `"132"`
3. `"213"`
4. `"231"`
5. `"312"`
6. `"321"`
Given `n` and `k`, return the `kth` permutation sequence.
**Example 1:**
**Input:** n = 3, k = 3
**Output:** "213"
**Example 2:**
**Input:** n = 4, k = 9
**Output:** "2314"
**Example 3:**
**Input:** n = 3, k = 1
**Output:** "123"
**Constraints:**
* `1 <= n <= 9`
* `1 <= k <= n!`