Find the Union and Intersection of the two sorted arrays in Java

October 13, 2022

Find the Union & Interaction of the two sorted arrays

Here, in this page we will discuss the program to find the union and interaction of two sorted arrays in Java . We are given with two sorted arrays and we have to find the union and interaction of the given two arrays

Find the Union & Interaction of the two sorted arrays

Algorithm to find Union :

  • Use two index variables i and j, initial values i = 0, j = 0
  • If arr1[i] is smaller than arr2[j] then print arr1[i] and increment i.
  • If arr1[i] is greater than arr2[j] then print arr2[j] and increment j. 
  • If both are same then print any of them and increment both i and j.
  • Print remaining elements of the larger array.

Algorithm to find Interaction :

  • Use two index variables i and j, initial values i = 0, j = 0.
  • If arr1[i] is smaller than arr2[j] then increment i.
  • If arr1[i] is greater than arr2[j] then increment j.
  • If both are same then print any of them and increment both i and j.

Java Code

Run 

import java.util.*;
public
class Main {
    public
    static void Union(int[] arr1, int[] arr2) {
        int i = 0;
        int j = 0;

        while (i < arr1.length && j < arr2.length) {
            if (arr1[i] < arr2[j]) {
                System.out.print(arr1[i] + " ");
                i++;
            } 
           else if (arr2[j] < arr1[i]) {
                System.out.print(arr2[j] + " ");
                j++;
            } else {
                System.out.print(arr1[i] + " ");

                i++;
                j++;
            }

        }
        while (i < arr1.length) {
            System.out.print(arr1[i] + " ");
            i++;
        }
        while (j < arr2.length) {
            System.out.print(arr2[j] + " ");
            j++;
        }
    }
    public
    static void Intersection(int[] arr1, int[] arr2) {
        int i = 0;
        int j = 0;
        while (i < arr1.length && j < arr2.length) {
            if (arr1[i] < arr2[j]) {
                i++;
            } else if (arr1[i] > arr2[j]) {
                j++;
            } else {
                System.out.print(arr1[i] + " ");
                i++;
                j++;
            }
        }
    }
    public
    static void main(String[] args) throws Exception {
        Scanner scn = new Scanner(System.in);
       
        int n1 = 3;
         System.out.println("The size of the array 1:- "+n1);
         int[] arr1 = new int[]{ 1,2,3}; 
        System.out.println("The Elements of array 1");
        for (int i = 0; i < n1; i++) {
            System.out.print(arr1[i] + " ");
        }
        System.out.println();

       
        int n2 = 4;
         System.out.println("The size of the array 2:- "+n2);

         int[] arr2 = new int[]{4,5,6,7}; 
        System.out.println("The Elements of array 2");
        

        for (int i = 0; i < n2; i++) {
            System.out.print(arr2[i] + " ");
        }
        System.out.println();
        System.out.println("The Union of the two array is ");
        Union(arr1, arr2);
        System.out.println();
        Intersection(arr1, arr2);
    }
}

Output:-

The size of the array 1:- 3
The Elements of array 1
1 2 3 
The size of the array 2:- 4
The Elements of array 2
4 5 6 7 
The Union of the two array is 
1 2 3 4 5 6 7

Given an array which consists of only 0, 1 and 2

Move all the negative elements to one side of the array

Find the Union and Intersection of the two sorted arrays

Find Largest sum contiguous Subarray

Minimize the maximum difference between heights 

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2 comments on “Find the Union and Intersection of the two sorted arrays in Java”


  • NAZIA KHAN

    public static void main(String[] args) {
    //for union
    int[] a={1,6,2,5,6,9,3};
    int[] b={2,5,8,2,7,1};
    Set s=new TreeSet();
    for(int i:a){
    s.add(i);
    }
    for(int i:b){
    s.add(i);
    }
    List ls=new ArrayList(s);
    Collections.sort(ls);
    for(int i:ls){
    System.out.print(i+” “);
    }
    System.out.println();

    //for intersection
    Set u=new TreeSet();
    List lu=new ArrayList();
    for(int i:a){
    u.add(i);
    }

    for(int i:b){
    if(u.contains(i)&& !lu.contains(i)){
    lu.add(i);
    }
    }
    Collections.sort(lu);
    for(int i:lu){
    System.out.print(i+” “);
    }
    }


  • Gyanendra

    import java.util.*;
    public class Main{
    public static void main(String[] args){
    Scanner scn=new Scanner(System.in);
    int n1=scn.nextInt();
    int[] arr1=new int[n1];

    for(int i=0;i<n1;i++){
    arr1[i]=scn.nextInt();
    }

    int n2=scn.nextInt();
    int[] arr2=new int[n2];
    for(int i=0;i<n2;i++){
    arr2[i]=scn.nextInt();
    }

    int i=0,j=0,k=0;
    int[] ans=new int[arr1.length+arr2.length];

    while(i<arr1.length && j<arr2.length){

    if(arr1[i]arr2[j]){
    ans[k]=arr2[j];
    j++;
    k++;
    }
    else{
    ans[k]=arr1[i];
    i++;
    j++;
    k++;
    }
    }

    while(i<arr1.length){
    ans[k]=arr1[i];
    i++;
    k++;
    }

    while(j<arr2.length){
    ans[k]=arr2[j];
    j++;
    k++;
    }

    for(int temp:ans)
    System.out.print(temp+" ");
    }
    }