961. N-Repeated Element in Size 2N Array

Description

In a array A of size 2N, there are N+1 unique elements, and exactly one of these elements is repeated N times.

Return the element repeated N times.

Example 1:

Input: [1,2,3,3]

Output: 3

Example 2:

Input: [2,1,2,5,3,2]

Output: 2

Example 3:

Input: [5,1,5,2,5,3,5,4]

Output: 5

Note:

<li><code>4 &lt;= A.length &lt;= 10000</code></li>

<li><code>0 &lt;= A[i] &lt; 10000</code></li>

<li><code>A.length</code> is even</li>