Contains_Duplicate.cpp

// Question Link: https://leetcode.com/problems/contains-duplicate/
// Question: Given an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.
/* Example 1:
    Input: nums = [1,2,3,1]
    Output: true

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

   Example 3:
    Input: nums = [1,1,1,3,3,4,3,2,4,2]
    Output: true
*/

//Solution

#include<unordered_map>

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        unordered_map<int, int> m;
        for(int i=0; i<nums.size(); i++)
        {
            m[nums[i]]++;
        }
        for(auto p:m)
        {
            if(p.second > 1)
                return true;
        }
        return false;
    }
};