PrintIntersection.java

// Print Intersection
// Send Feedback
// You have been given two integer arrays/list(ARR1 and ARR2) of size N and M,
// respectively. You need to print their intersection; An intersection for this
// problem can be defined when both the arrays/lists contain a particular value
// or to put it in other words, when there is a common value that exists in both
// the arrays/lists.
// Note :
// Input arrays/lists can contain duplicate elements.

// The intersection elements printed would be in ascending order.

// Input format :
// The first line contains an Integer 't' which denotes the number of test cases
// or queries to be run. Then the test cases follow.

// The first line of each test case or query contains an integer 'N'
// representing the size of the first array/list.

// The second line contains 'N' single space separated integers representing the
// elements of the first the array/list.

// The third line contains an integer 'M' representing the size of the second
// array/list.

// The fourth line contains 'M' single space separated integers representing the
// elements of the second array/list.
// Output format :
// For each test case, print the intersection elements in a row, separated by a
// single space.

// Output for every test case will be printed in a separate line.
// Constraints :
// 1 <= t <= 10^2
// 0 <= N <= 10^4
// 0 <= M <= 10^4

// Time Limit: 1 sec
// Sample Input 1 :
// 2
// 6
// 2 6 8 5 4 3
// 4
// 2 3 4 7
// 2
// 10 10
// 1
// 10
// Sample Output 1 :
// 2 3 4
// 10
// Sample Input 2 :
// 1
// 4
// 2 6 1 2
// 5
// 1 2 3 4 2
// Sample Output 2 :
// 1 2 2
// Explanation for Sample Output 2 :
// Since, both input arrays have two '2's, the intersection of the arrays also
// have two '2's. The first '2' of first array matches with the first '2' of the
// second array. Similarly, the second '2' of the first array matches with the
// second '2' if the second array.

import java.util.Arrays;
import java.util.HashMap;

public class Solution {

    public static void intersection(int[] arr1, int[] arr2) {
        // Your code goes here
        HashMap<Integer, Integer> map = new HashMap<>();
        for (int i : arr1) {
            if (map.containsKey(i)) {
                map.put(i, map.get(i) + 1);
            } else {
                map.put(i, 1);
            }
        }

        Arrays.sort(arr2)
        for (int i : arr2) {
            if (map.containsKey(i)) {
                if (map.get(i) > 0) {
                    System.out.print(i + " ");
                    map.put(i, map.get(i) - 1);
                }
            }
        }
    }
}