编辑器
import java.util.LinkedHashSet; public class Main { public static void main(String[] args) { LinkedHashSet<String> cars = new LinkedHashSet<String>(); cars.add("Volvo"); cars.add("BMW"); cars.add("Ford"); cars.add("BMW"); cars.add("Mazda"); System.out.println(cars.contains("Mazda")); } }
true
编辑器