How leetcode returns a subarray of K different integers

This article will explain in detail how leetcode returns a subarray of K different integers. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.

Given a positive integer array A, if the number of different integers in a subarray of A happens to be K, the continuous and not necessarily independent subarray of An is called a good subarray.

(for example, there are three different integers in [1Pert 2, 3pr 1], and 3. )

Returns the number of good subarrays in A.

Example 1:

Output: a = [1, 2, 2, 1, 1, 2, 3], K = 2

Enter: 7

Explanation: a subarray that happens to be composed of two different integers: [1], [2], [1], [2], [2], [2], [2].

Example 2:

Input: a = [1, 2, 1, 3, 4], K = 3

Output: 3

Explanation: a subarray of exactly three different integers: [1], [2], [3], [3].

Tip:

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