N-Repeated Element in Size 2N Array(LeetCode 961):

Problem

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.