In an array containing n + 1 integers where each integer is between 1 and n (inclusive), there is exactly one duplicate number. Find this duplicate number without modifying the array and using only constant extra space.

• An array of integers nums.

• An integer representing the duplicate value.

• 1 <= n <= 10^5
• nums.length == n + 1
• 1 <= nums[i] <= n
• All the integers in nums appear only once except for one integer which appears two or more times.

Input: nums = [1, 3, 4, 2, 2]
Output: 2
Explanation: 2 is the repeating integer.