Find The Duplicate Number

Try to solve the Find The Duplicate Number problem.


Given an array of positive numbers, nums, such that the values lie in the range [1,n][1, n], inclusive, and that there are n+1n+1 numbers in the array, find and return the duplicate number present in nums. There is only one repeated number in nums.

Note: You cannot modify the given array nums. You have to solve the problem using only constant extra space.


  • 1n1031 \leq n \leq 10^3
  • nums.length =n+1= n + 1
  • 11 \leq nums[i] n\leq n
  • All the integers in nums are unique, except for one integer that will appear more than once.


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