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N-Repeated Element in Size 2N Array

Problem statement​

You are given an integer array nums with the following properties:

  • nums.length == 2 * n.
  • nums contains n + 1 unique elements.
  • Exactly one element of nums is repeated n times.

Return the element that is repeated n times.

Example 1:

Input: nums = [1,2,3,3]Output: 3

Example 2:

Input: nums = [2,1,2,5,3,2]Output: 2

Example 3:

Input: nums = [5,1,5,2,5,3,5,4]Output: 5

Constraints:

  • 2 <= n <= 5000
  • nums.length == 2 * n
  • 0 <= nums[i] <= 104
  • nums contains n + 1 unique elements and one of them is repeated exactly n times.

My solution​

/**
 * @param {number[]} nums
 * @return {number}
 */
var repeatedNTimes = function(nums) {
    const set = new Set();
    
    for (const num of nums) {
        if (!set.has(num)) {
            set.add(num)
        } else {
            return num
        }
    }
};