题解 | 序列找数

import java.util.*;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 输入的全部数字
        final List<Integer> lists = new ArrayList<>();
        for (String number : in.nextLine().split(" ")) {
            lists.add(Integer.valueOf(number));
        }
        final int max = lists.get(0);

        // 0到max - 1的数字
        final Map<Integer,Integer> numbers = new HashMap<>();
        for(int index= 0; index != max;index++) {
            numbers.put(index,index);
        }

        final List<Integer> hasNumbers = new ArrayList<>();
        for (int hasNumber : numbers.values()) {
            lists.forEach(number -> {
                if (number == hasNumber) hasNumbers.add(number);
            });
        }

        for(int hasNumber : hasNumbers) {
            numbers.remove(hasNumber);
        }
        for (Integer value : numbers.values()) {
            System.out.println(value);
        }
    }
}