unionOfTwoArrays.cpp

/* Q-Given two arrays A and B of size N and M respectively. The task is to find union between these two arrays.
Union of the two arrays can be defined as the set containing distinct elements from both the arrays. If there are repetitions,
then only one occurrence of element should be printed in union */
#include <bits/stdc++.h>
using namespace std;

int doUnion(int *, int , int *, int);

int main() {
	    int n, m;
	    cin >> n >> m;
	    int a[n], b[m];
	    for(int i = 0;i<n;i++)
	       cin >> a[i];
	    for(int i = 0;i<m;i++)
	       cin >> b[i];
	    cout << doUnion(a, n, b, m) << endl;
	return 0;
}

// a and b : given array with n and m size respectively
int doUnion(int a[], int n, int b[], int m)  {
    int un[m+n],u=0,i,j,c;
    //iterating first array
    for(j=0;j<n;j++)
    {
	//iterating unioun array
        for(i=0;i<u;i++)
        {
	    //checking if element at j index is already present in union array or not,if found present then break loop
            if(a[j]==un[i])
                break;
        }
	 //checking if the element is found or not,if not found then adding it in unioun array
	 if(i==u)
            un[u++]=a[j];
    }
    //iterating first array 	
    for(j=0;j<m;j++)
    {
	//iterating unioun array    
        for(i=0;i<u;i++)
        {
      	       //checking if element at j index is already present in union array or not,if found present then break loop
	       if(b[j]==un[i])
                     break;
        }
	//checking if the element is found or not,if not found then adding it in unioun array
        if(i==u)
            un[u++]=b[j];
    }
    return u;
}