2200\. Find All K-Distant Indices in an Array

Easy

You are given a **0-indexed** integer array `nums` and two integers `key` and `k`. A **k-distant index** is an index `i` of `nums` for which there exists at least one index `j` such that `|i - j| <= k` and `nums[j] == key`.

Return _a list of all k-distant indices sorted in **increasing order**_.

**Example 1:**

**Input:** nums = [3,4,9,1,3,9,5], key = 9, k = 1

**Output:** [1,2,3,4,5,6]

**Explanation:** Here, nums[2] == key and nums[5] == key.

- For index 0, |0 - 2| > k and |0 - 5| > k, so there is no j where |0 - j| <= k and nums[j] == key. Thus, 0 is not a k-distant index.

- For index 1, |1 - 2| <= k and nums[2] == key, so 1 is a k-distant index.

- For index 2, |2 - 2| <= k and nums[2] == key, so 2 is a k-distant index.

- For index 3, |3 - 2| <= k and nums[2] == key, so 3 is a k-distant index.

- For index 4, |4 - 5| <= k and nums[5] == key, so 4 is a k-distant index.

- For index 5, |5 - 5| <= k and nums[5] == key, so 5 is a k-distant index.

- For index 6, |6 - 5| <= k and nums[5] == key, so 6 is a k-distant index.

Thus, we return [1,2,3,4,5,6] which is sorted in increasing order. 

**Example 2:**

**Input:** nums = [2,2,2,2,2], key = 2, k = 2

**Output:** [0,1,2,3,4]

**Explanation:** For all indices i in nums, there exists some index j such that |i - j| <= k and nums[j] == key, so every index is a k-distant index.

Hence, we return [0,1,2,3,4]. 

**Constraints:**

*   `1 <= nums.length <= 1000`
*   `1 <= nums[i] <= 1000`
*   `key` is an integer from the array `nums`.
*   `1 <= k <= nums.length`