Question

Java

Write a method intersect_or_union_fcn() that gets vectors of type integer v1, v2, and v3 and determines if the vector v3 is the intersection or union of vectors v1 and v2.

Example 1: If v1 = {2, 3, 1, 5}, v2 = {3, 4, 5} and v3 = {3, 5}, then:

              intersect_or_union_fcn(v1, v2, v3) will print:

                             v3 is the intersection of v1 and v2

Example 2: If v1 = {2, 3, 1, 5}, v2 = {3, 4, 5} and v3 = {2, 3, 1, 5, 4}, then:

              intersect_or_union_fcn(v1, v2, v3) will print:

                             v3 is the union of v1 and v2

Example 3: If v1 = {2, 3, 1, 5}, v2 = {3, 4, 5} and v3 = {2, 3, 1, 5, 4, 6}, then:

              intersect_or_unition_fcn(v1, v2, v3) will print:

                             v3 is neither the intersection nor the union of v1 and v2.

Write a test program that prompts the user to enter three vectors and test your program with all the three examples above.

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Answer 1

Thanks for the question. Below is the code you will be needing. Let me know if you have any doubts or if you need anything to change. 

If you are satisfied with the solution, please rate the answer.


Thank You !

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import java.util.Arrays;
import java.util.Scanner;

public class IntersectionUnion {

    public static String intersect_or_union_fcn(int[] v1, int[] v2, int[] v3) {

        // first search v3 elements in v1
        boolean containsAllInV1 = true;
        for (int num : v3) {
            boolean flag = false;
            for (int numv1 : v1) {
                if (num == numv1) {
                    flag = true;
                    break;
                }
            }
            if (!flag) {
                containsAllInV1 = false;
                break;
            }
        }
        // second search v3 elements in v2
        boolean containsAllInV2 = true;
        for (int num : v3) {
            boolean flag = false;
            for (int numv2 : v2) {
                if (num == numv2) {
                    flag = true;
                    break;
                }
            }
            if (!flag) {
                containsAllInV2 = false;
                break;
            }
        }

        // when each element in v3 found in both v1 and v2
        if (containsAllInV1 && containsAllInV2) return "v3 is the intersection of v1 and v2";

        // when its not an intersection

            int[] unionArray = new int[v1.length+v2.length];
            System.arraycopy(v1,0,unionArray,0,v1.length);
            System.arraycopy(v2,0,unionArray,v1.length,v2.length);
            //System.out.println(Arrays.toString(unionArray));
            for(int num: v3){
                boolean found = false;
                for(int numUnion: unionArray){
                    if(num==numUnion){
                        found=true;
                        break;
                    }
                }
                if(!found)return "v3 is neither the intersection nor the union of v1 and v2";
            }

        return "v3 is the union of v1 and v2";
    }


    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        System.out.println("Vector 1");
        int v1[] = getVector(scanner);
        System.out.println("Vector 2");
        int v2[] = getVector(scanner);
        System.out.println("Vector 3");
        int v3[] = getVector(scanner);

        System.out.println("Result = " + intersect_or_union_fcn(v1, v2, v3));


    }

    public static int[] getVector(Scanner scanner) {

        System.out.print("Input number of elements in the vector: ");
        int size = scanner.nextInt();

        int[] vector = new int[size];
        for (int i = 0; i < size; i++) {

            System.out.print("Enter element #" + (i + 1) + ": ");
            vector[i] = scanner.nextInt();
        }

        return vector;
    }
}