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 <= 91 <= k <= n!