Find Duplicate Number/lletcode/gfg/codechef

 1. Find the Duplicate Number

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 uses only constant extra space.

 

Example 1:

Input: nums = [1,3,4,2,2]
Output: 2

Example 2:

Input: nums = [3,1,3,4,2]
Output: 3

Solution

class Solution {
public:
    int findDuplicate(vector<int>& nums) {
      sort(nums.begin(),nums.end());
        for(int i=1;i<nums.size();i++){
            if(nums[i]==nums[i-1]){
                return nums[i];
            }
        }
        return -1;
    }
};