2856. Count Complete Subarrays in an Array

Medium
Array
Hash Table
Sliding Window

Description

You are given an array nums consisting of positive integers.

We call a subarray of an array complete if the following condition is satisfied:

  • The number of distinct elements in the subarray is equal to the number of distinct elements in the whole array.

Return the number of complete subarrays.

A subarray is a contiguous non-empty part of an array.

 

Example 1:

Input: nums = [1,3,1,2,2]
Output: 4
Explanation: The complete subarrays are the following: [1,3,1,2], [1,3,1,2,2], [3,1,2] and [3,1,2,2].

Example 2:

Input: nums = [5,5,5,5]
Output: 10
Explanation: The array consists only of the integer 5, so any subarray is complete. The number of subarrays that we can choose is 10.

 

Constraints:

  • 1 <= nums.length <= 1000
  • 1 <= nums[i] <= 2000

Hints

Hint 1
Let’s say k is the number of distinct elements in the array. Our goal is to find the number of subarrays with k distinct elements.
Hint 2
Since the constraints are small, you can check every subarray.

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