zoukankan      html  css  js  c++  java
  • POJ 1028题目描述

    Description

    Standard web browsers contain features to move backward and forward among the pages recently visited. One way to implement these features is to use two stacks to keep track of the pages that can be reached by moving backward and forward. In this problem, you are asked to implement this. 
    The following commands need to be supported: 
    BACK: Push the current page on the top of the forward stack. Pop the page from the top of the backward stack, making it the new current page. If the backward stack is empty, the command is ignored. 
    FORWARD: Push the current page on the top of the backward stack. Pop the page from the top of the forward stack, making it the new current page. If the forward stack is empty, the command is ignored. 
    VISIT : Push the current page on the top of the backward stack, and make the URL specified the new current page. The forward stack is emptied. 
    QUIT: Quit the browser. 
    Assume that the browser initially loads the web page at the URL http://www.acm.org/

    Input

    Input is a sequence of commands. The command keywords BACK, FORWARD, VISIT, and QUIT are all in uppercase. URLs have no whitespace and have at most 70 characters. You may assume that no problem instance requires more than 100 elements in each stack at any time. The end of input is indicated by the QUIT command.

    Output

    For each command other than QUIT, print the URL of the current page after the command is executed if the command is not ignored. Otherwise, print "Ignored". The output for each command should be printed on its own line. No output is produced for the QUIT command.

    Sample Input

    VISIT http://acm.ashland.edu/
    VISIT http://acm.baylor.edu/acmicpc/
    BACK
    BACK
    BACK
    FORWARD
    VISIT http://www.ibm.com/
    BACK
    BACK
    FORWARD
    FORWARD
    FORWARD
    QUIT

    Sample Output

    http://acm.ashland.edu/
    http://acm.baylor.edu/acmicpc/
    http://acm.ashland.edu/
    http://www.acm.org/
    Ignored
    http://acm.ashland.edu/
    http://www.ibm.com/
    http://acm.ashland.edu/
    http://www.acm.org/
    http://acm.ashland.edu/
    http://www.ibm.com/
    Ignored
  • 相关阅读:
    浅议tomcat与classloader
    业务系统的JVM启动参数推荐
    Nginx负载趟过的坑
    linux 建立反向shell
    rpm -e 包名 卸载安装的二进制包
    源码安装natcat
    取消密码登录
    ssh-copy-id 安全地复制公钥到远程服务器上
    iptables允许一个ip访问本机的某个端口
    zookeeper 安装 配置集群
  • 原文地址:https://www.cnblogs.com/guochen/p/5379702.html
Copyright © 2011-2022 走看看