Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.
Find all the elements that appear twice in this array.
Input: [4, 3, 2, 7, 8, 2, 3, 1]
Output: [2, 3]Given an array of integers, 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.
Find all the elements that appear twice in this array.
Input: [4, 3, 2, 7, 8, 2, 3, 1]
Output: [2, 3]