0992. Subarrays with K Different Integers

https://leetcode.com/problems/subarrays-with-k-different-integers

Description

Given an integer array nums and an integer k, return the number of good subarrays of nums.

A good array is an array where the number of different integers in that array is exactly k.

• For example, [1,2,3,1,2] has 3 different integers: 1, 2, and 3.

A subarray is a contiguous part of an array.

Example 1:

**Input:** nums = [1,2,1,2,3], k = 2
**Output:** 7
**Explanation:** Subarrays formed with exactly 2 different integers: [1,2], [2,1], [1,2], [2,3], [1,2,1], [2,1,2], [1,2,1,2]

Example 2:

**Input:** nums = [1,2,1,3,4], k = 3
**Output:** 3
**Explanation:** Subarrays formed with exactly 3 different integers: [1,2,1,3], [2,1,3], [1,3,4].

Constraints:

• 1 <= nums.length <= 2 * 104

• 1 <= nums[i], k <= nums.length

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