Union and Intersection of Arrays C++

Union and Intersection of Arrays

Let us suppose we have two sorted Arrays

int Arr1[]={1, 3, 4, 5, 7};

int Arr2[]={2, 3, 5, 6};

then UNION will be: {1, 2, 3, 4, 5, 6, 7}

INTERSECTION : {3, 5}

C++ Program for UNION of arrays:

#include<iostream>
#include<stdio.h>

using namespace std;

/* Function prints union of arr1[] and arr2[]
   m is the number of elements in arr1[]
   n is the number of elements in arr2[] */

int printUnion(int arr1[], int arr2[], int m, int n)
{
  int i = 0, j = 0;
  while(i < m && j < n)
  {
    if(arr1[i] < arr2[j])
      cout<<arr1[i++];
    else if(arr2[j] < arr1[i])
      cout<<arr2[j++];
    else
    {
      cout<<arr2[j++];
      i++;
    }
  }

  /* Print remaining elements of the larger array */
  while(i < m)
   cout<<arr1[i++];
  while(j < n)
   cout<<arr2[j++];
}

/* Driver program to test above function */
int main()
{
  int arr1[] = {1, 2, 4, 5, 6};
  int arr2[] = {2, 3, 5, 7};
  int m = sizeof(arr1)/sizeof(arr1[0]);
  int n = sizeof(arr2)/sizeof(arr2[0]);
  printUnion(arr1, arr2, m, n);
  getchar();
  return 0;
}

 

OUTPUT:

union and intersection of arrays

C++ Program for INTERSECTION of arrays:

#include<iostream>
#include<stdio.h>
using namespace std;

/* Function prints Intersection of arr1[] and arr2[]
   m is the number of elements in arr1[]
   n is the number of elements in arr2[] */
int printIntersection(int arr1[], int arr2[], int m, int n)
{
  int i = 0, j = 0;
  while(i < m && j < n)
  {
    if(arr1[i] < arr2[j])
      i++;
    else if(arr2[j] < arr1[i])
      j++;
    else /* if arr1[i] == arr2[j] */
    {
      cout<<arr2[j++];
      i++;
    }
  }
}


int main()
{
  int arr1[] = {1, 2, 4, 5, 6};
  int arr2[] = {2, 3, 5, 7};
  int m = sizeof(arr1)/sizeof(arr1[0]);
  int n = sizeof(arr2)/sizeof(arr2[0]);
  printIntersection(arr1, arr2, m, n);
  getchar();
  return 0;
}

 

OUTPUT:

union and intersection of arrays

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