9月6号笔试题

第二题

public ListNode sortList(ListNode head) {
    ListNode temp = head;
    TreeMap<Integer, Integer> map = new TreeMap<>();
    while (temp != null) {
        map.put(temp.val, map.getOrDefault(temp.val, 0) + 1);
        temp = temp.next;
    }
    temp = head;
    while (temp != null) {
        for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
            Integer key = entry.getKey();
            Integer num = entry.getValue();
            if (num == 0) {
                break;
            }
            map.put(key, num - 1);
            temp.val = key;
            temp = temp.next;
        }
    }
    return head;
}

第三题

package FreeTime;

import java.util.ArrayDeque;
import java.util.HashMap;
import java.util.Objects;
import java.util.Scanner;
public class BS_3 {

    HashMap<Integer, Integer> map = new HashMap<>();
    ArrayDeque<Info> deque = new ArrayDeque<>();
    ArrayDeque<Info> tempDeque = new ArrayDeque<>();

    public void in(int index, String s) {
        deque.add(new Info(index, s));
        map.put(index, map.getOrDefault(index, 0) + 1);
    }

    public String out(int index) {
        if (deque.isEmpty() || map.isEmpty() || (index != 0 && !map.containsKey(index))) {
            return "-1";
        }
        if (index == 0) {
            Info poll = deque.poll();
            map.put(poll.index, map.getOrDefault(poll.index, 0) - 1);
            if (map.get(poll.index) <= 0) {
                map.remove(poll.index);
            }
            return poll.value;
        }
        Info element = null;
        while (!deque.isEmpty() && (element = deque.poll()).index != index) {
            tempDeque.addFirst(element);
        }
        while (!tempDeque.isEmpty()) {
            deque.addFirst(Objects.requireNonNull(tempDeque.pollFirst()));
        }
        map.put(index, map.get(index) - 1);
        if (map.get(index) == 0) {
            map.remove(index);
        }
        return element == null ? "-1" : element.value;
    }

    public static void main(String[] args) {
        BS_3 bs_3 = new BS_3();
        Scanner in = new Scanner(System.in);
        int operateNum = Integer.parseInt(in.nextLine());
        for (int i = 0; i < operateNum; i++) {
            String line = in.nextLine();
            String[] tokens = line.split(" ");
            if (tokens[0].equals("in")) {
                int index = Integer.parseInt(tokens[1]);
                bs_3.in(index, tokens[2]);
            } else if (tokens[0].equals("out")) {
                int index = Integer.parseInt(tokens[1]);
                System.out.println(bs_3.out(index));
            }
        }
    }

    static class Info {
        int index;
        String value;

        public Info(int index, String value) {
            this.index = index;
            this.value = value;
        }
    }
}