Java利用set去重

import java.util.HashSet;
import java.util.Scanner;

//去重
public class E {
    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        HashSet<String> set = new HashSet<>();
        String str = cin.nextLine();
        String arr[] = str.split(" ");
        for (int i = 0; i < arr.length; i++) {
            set.add(arr[i]);
        }
        System.out.println(set.size());//輸出有幾種不一樣的字符串
    }
}

輸入 

qwe q e we we we qwe we e e qwe

輸出 

4