IntersectionOfTwoArraysII.java

package LeetcodePractice;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class IntersectionOfTwoArraysII {
    public static int[] intersect(int[] nums1, int[] nums2) {
        Map<Integer, Integer> map = new HashMap<>();
        List<Integer> list = new ArrayList<>();
        for (int n : nums1) map.put(n, map.getOrDefault(n, 0) + 1);
        for (int n : nums2) {
            if (map.getOrDefault(n, 0) > 0) {
                list.add(n);
                map.put(n, map.get(n) - 1);
            }
        }
        int[] result = new int[list.size()];
        for (int i = 0; i < list.size(); i++) result[i] = list.get(i);
        return result;
    }

    public static void main(String[] args) {
        int[] nums1 = {1, 2, 2, 1};
        int[] nums2 = {2, 2};
        System.out.println(Arrays.toString(intersect(nums1, nums2)));
        int[] nums3 = {4, 9, 5};
        int[] nums4 = {9, 4, 9, 8, 4};
        System.out.println(Arrays.toString(intersect(nums3, nums4)));
    }
}