#2913 - Subarrays Distinct Element Sum of Squares I

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Array Hash Table

Problem Description

You are given a 0-indexed integer array nums.

The distinct count of a subarray of nums is defined as:

Let nums[i..j] be a subarray of nums consisting of all the indices from i to j such that 0 <= i <= j < nums.length. Then the number of distinct values in nums[i..j] is called the distinct count of nums[i..j].

Return the sum of the squares of distinct counts of all subarrays of nums.

A subarray is a contiguous non-empty sequence of elements within an array.

Solution

/**
 * @param {number[]} nums
 * @return {number}
 */
var sumCounts = function(nums) {
  let result = 0;

  for (let i = 0; i < nums.length; i++) {
    const set = new Set();
    for (let j = i; j < nums.length; j++) {
      set.add(nums[j]);
      result += set.size * set.size;
    }
  }

  return result;
};