https://leetcode.com/problems/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 for n = 3:

"123" "132" "213" "231" "312" "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!