Get uncommon elements from two sorted arrays in C++

In this tutorial, we will be learning about how to get uncommon elements from two sorted arrays in C++.

Approach 1

The sample example code is as follows…

#include <iostream>
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,m;
    cout<<"Enter the array size of two arrays\n";
    cin>>m>>n;
    int arr1[m],arr2[n];
    cout<<"Enter the sorted array elements\n";
    for(int i=0;i<m;i++)
    {
        cin>>arr1[i];
    }
    for(int i=0;i<n;i++)
    {
        cin>>arr2[i];
    }
    cout<<"\nThe Uncommmon elements are : ";
    vector<int>v;
    for(int i=0;i<m;i++)
    {
        for(int j=0;j<n;j++)
        {
            if(arr1[i]==arr2[j])
            v.push_back(arr1[i]);
        }
    }
    std::vector<int>::iterator it;
    for(int i=0;i<m;i++)
    {
        it=std::find(v.begin(),v.end(),arr1[i]);
        if(it==v.end())
        cout<<arr1[i]<<" ";
    }
    for(int i=0;i<n;i++)
    {
        it=std::find(v.begin(),v.end(),arr2[i]);
        if(it==v.end())
        cout<<arr2[i]<<" ";
    }
    return 0;
}

Output :

Enter the array size of two arrays
3
5
Enter the sorted array elements
1 2 3
3 4 1 5 6

The Uncommmon elements are : 2 4 5 6

Explanation :

• Here first, we need to take the size of two sorted arrays from the user.
• Then the user needs to enter the elements of two sorted arrays.
• Then here we have declared a vector so that the common elements are pushed into it.
• Then by running the two separate for loops we need to print the elements which are not in the vector.

Approach 2

The sample example code is as follows…

#include <iostream>
#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n,m; 
    cout<<"Enter the array size of two arrays\n"; 
    cin>>m>>n; 
    int arr1[m],arr2[n]; 
    map<int,int>mp;
    cout<<"Enter the sorted array elements\n"; 
    for(int i=0;i<m;i++) 
    { 
        cin>>arr1[i]; 
        mp[arr1[i]]++;
        
    } 
    for(int i=0;i<n;i++) 
    { 
        cin>>arr2[i]; 
        mp[arr2[i]]++;
    }
    cout<<"The Uncommon elements are : ";
    for(auto it :mp)
    {
        if(it.second==1)
        cout<<it.first<<" ";
    }
    return 0;
}

Output :

Enter the array size of two arrays
5 7
Enter the sorted array elements
1 4 6 7 8
1 2 3 4 5 6 7
The Uncommon elements are : 2 3 5 8

Explanation :

• Generally, here we need to take the sizes of two sorted arrays.
• Then we need to take the elements of two sorted arrays.
• Then here we have used a map data structure for storing the elements and their occurrence( key as element and value as its count of occurrence).
• At last, we need to return the element(key) whose value is equal to one.