27. Find Duplicate in Range 0 and n-1

You are given an array of n integers. Each number is guaranteed to be in the range [0, n-1], and exactly one number is repeated once. Write a program to find and print the repeated number.

You cannot modify the array and cannot use extra memory (O(1) space).

Example-1

Input: n = 5 , arr = [0 1 2 3 2]
Output: 2

Example-2

Input: n = 6, arr = [5 4 3 2 1 3]
Output: 3

Example-3

Input: n = 4, arr = [1 0 2 0]
Output: 0