Print Non-Repeated Elements

Problem Statement - link #

Hashing is very useful to keep track of the frequency of the elements in a list.

You are given an array of integers. You need to print the non-repeated elements as they appear in the array.

Your Task: You don’t need to read input or print anything. You only need to complete the function printNonRepeated() that takes arr and n as parameters and return the array which has the distinct elements in same order as they appear in input array. The newline is appended automatically by the driver code.

Expected Time Complexity: O(n)
Expected Auxiliary Space: O(n)

Examples #

Example 1:

Input:
n = 10
arr[] = {1,1,2,2,3,3,4,5,6,7}
Output: 4 5 6 7
Explanation: 4, 5, 6 and 7 are the only 
elements which is having only 1 
frequency and hence, Non-repeating.

Example 2:

Input:
n = 5
arr[] = {10,20,40,30,10}
Output: 20 40 30
Explanation: 20, 40, 30 are the only 
elements which is having only 1 
frequency and hence, Non-repeating.

Constraints #

• 1 <= N < 1000
• 0 <= arr[i] <= 10^7

Solutions #

class Solution{
    public:
    // arr[]: input array
    // n: size of array
    //Function to return non-repeated elements in the array.
    vector<int> printNonRepeated(int arr[],int n)
    {
        //Your code here
        map<int, int> m;
        vector<int> res;
        for(int i=0; i<n; i++) m[arr[i]]++;
        for(int i=0; i<n; i++)
            if(m[arr[i]]==1)
                res.push_back(arr[i]);
        return res;
    }
};