HDU-1702

在这里插入图片描述

我自己手写了一个简易的栈和队列，嫌麻烦的同学可以直接用LinkedList哈。

import java.util.Scanner;public class Main {
    public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);while (sc.hasNext()) {
    int n = sc.nextInt();for (int i = 0; i < n; i++) {
    int m = sc.nextInt();String str = sc.next();stack s = new stack();queue q = new queue();for (int j = 0; j < m; j++) {
    if(str.equals("FIFO")){
     //队列操作String ss = sc.next();if(ss.equals("IN")){
    Node node = new Node(sc.nextInt());q.add(node);}else{
    if(q.isEmpty()) System.out.println("None");else System.out.println(q.remove());}}else{
     //栈操作String ss = sc.next();if(ss.equals("IN")){
    Node node = new Node(sc.nextInt());s.add(node);}else{
    if(s.isEmpty()) System.out.println("None");else System.out.println(s.pop());}}}}}}}//栈
class stack{
    Node head = new Node(0);public void add(Node newNode){
    newNode.next = head.next;head.next = newNode;}public int pop () {
    int num = head.next.data;head.next = head.next.next;return num;}//判空public boolean isEmpty(){
    if(head.next == null) return true;else return false;}
}class queue{
    Node head = new Node(0);public void add (Node newNode){
    Node temp = head;while(true){
    if(temp.next == null) break;temp = temp.next;}temp.next = newNode;}public int remove(){
    int num = head.next.data;head.next = head.next.next;return num;}//判空public boolean isEmpty(){
    if(head.next == null) return true;else return false;}
}class Node{
    int data;Node next;public Node(int data) {
    this.data = data;}
}