Preparing this workspace.
Permutation Sequence
Difficulty: Hard
Category: DSA
Topics: Math, Recursion
Asked at: Amazon, Adobe
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!`
Opening the problem
Progress is saved as you study.