Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive, there is only one repeated number in nums. Return this repeated number.
You must solve the problem without modifying the array nums and using only constant extra space.
Input: nums = [1,3,4,2,2]
Output: 2
Input: nums = [3,1,3,4,2]
Output: 3
Input: nums = [1,1]
Output: 1
nums appear only once except for precisely one integer which appears two or more times.