写代码，找出两个字符串数组中相同的字符串存到新的字符串中，使用hashset

时间复杂度：O(m+n)

package leetcode.arrayAndList;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Set;

public class CommentStr {
    public static void main(String[] args) {
        ArrayList ans = new ArrayList();

        // 两个字符串数组
        String[] array1 = {"apple", "banana", "orange", "grape"};
        String[] array2 = {"orange", "grape", "watermelon", "kiwi"};

        Set<String> mySet = new HashSet<>();

        for (String str:array1){
            mySet.add(str);
        }

        for (String str:array2){
            if(mySet.contains(str)){
                ans.add(str);
            }
        }

        System.out.println(ans);
    }
}