1852. Distinct Numbers in Each Subarray

https://leetcode.com/problems/distinct-numbers-in-each-subarray

Description

Given an integer array nums and an integer k, you are asked to construct the array ans of size n-k+1 where ans[i] is the number of distinct numbers in the subarray nums[i:i+k-1] = [nums[i], nums[i+1], ..., nums[i+k-1]].

Return the array ans.

Example 1:

**Input:** nums = [1,2,3,2,2,1,3], k = 3
**Output:** [3,2,2,2,3]
**Explanation:** The number of distinct elements in each subarray goes as follows:
- nums[0:2] = [1,2,3] so ans[0] = 3
- nums[1:3] = [2,3,2] so ans[1] = 2
- nums[2:4] = [3,2,2] so ans[2] = 2
- nums[3:5] = [2,2,1] so ans[3] = 2
- nums[4:6] = [2,1,3] so ans[4] = 3

Example 2:

**Input:** nums = [1,1,1,1,2,3,4], k = 4
**Output:** [1,2,3,4]
**Explanation:** The number of distinct elements in each subarray goes as follows:
- nums[0:3] = [1,1,1,1] so ans[0] = 1
- nums[1:4] = [1,1,1,2] so ans[1] = 2
- nums[2:5] = [1,1,2,3] so ans[2] = 3
- nums[3:6] = [1,2,3,4] so ans[3] = 4

Constraints:

• 1 <= k <= nums.length <= 105

• 1 <= nums[i] <= 105

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