Add implementation for Intersection and Union of Two Arrays using HashSet

Author: gourabofficial

Hashing/Question/IntersectionOfTwoArrays.java

@@ -0,0 +1,43 @@
+
+import java.util.HashSet;
+
+// intput -> arr1[] = {1,2,3,4,5,6,7,8,9} ;  
+//           arr2[] ={2,3,3,4,4,4,4,4,10};
+
+// commonly in both arrays.
+
+// output: [2,3,4]
+
+
+
+public class IntersectionOfTwoArrays {
+    public static void main(String[] args) {
+        int arr1[] = {1,2,3,4,5,6,7,8,9};
+        int arr2[] ={2,3,3,4,4,4,4,4,10,5};
+
+         FindIntersection(arr1, arr2);
+
+    }   
+
+    public static void FindIntersection(int arr1[], int arr2[]){
+        HashSet <Integer> set = new HashSet<>();
+        HashSet <Integer> result = new HashSet<>();
+
+        for (int num : arr1) {
+             set.add(num);
+        }
+
+        // check intersection
+
+        for (int num : arr2) {
+            if(set.contains(num))
+            result.add(num);
+        }
+
+        //Print the result
+        System.out.print("Intersection: ");
+        for (int value : result) {
+            System.out.println(value);
+        }
+    }
+}

Hashing/Question/UnionOfTwoArrays.java

@@ -0,0 +1,29 @@
+
+import java.util.HashSet;
+
+public class UnionOfTwoArrays {
+    public static void main(String[] args) {
+        int arr1[] = { 1, 2, 3, 4, 5, 6 };
+        int arr2[] = { 1, 2, 4 ,10};
+
+        int result = FindUnion(arr1, arr2);
+        System.out.println("The union of the two arrays is: " + result);  // (result -> 1,2,3,4,5,6,10)  size -> 7 
+    }
+
+    public static int FindUnion(int arr1[], int arr2[]) {
+
+        HashSet<Integer> set = new HashSet<>();
+
+        // for arr1
+        for (int num : arr1) {
+            set.add(num);
+        }
+
+        // for arr2
+        for (int num : arr2) {
+            set.add(num);
+        }
+
+        return set.size();
+    }
+}