import java.util.*;

public class Main{

    public static void main(String[] args){

        Deque<String> stack = new LinkedList();

        stack.push("student");

        stack.push("teacher");

        stack.push("president");//push:入栈

        while(!stack.isEmpty())//检查栈空

        {

            String s=stack.pop();//pop:出栈

            System.out.println(s);

        }

    }

}

import java.util.*;

public class Main{

    public static void main(String[] args){

        Deque<String> que = new LinkedList();

        que.offer("BJ");

        que.offer("HZ");

        que.offer("CQ");//offer:入栈

        while(!que.isEmpty())//检查栈空

        {

            String s=que.pop();//pop:出栈

            System.out.println(s);

        }

    }

}

import java.util.*;

class Edge implements Comparable{

    String to;

    int w;

    Edge(){}

    Edge(String to,int w)

    {

        this.to=to;

        this.w=w;

    }

    public int compareTo(Object o)

    {

        Edge e=(Edge)o;

        return w-e.w;    //由小到大

    }

}

public class Main{

    public static void main(String[] args){

        PriorityQueue<Edge> pque=new PriorityQueue();

        pque.offer(new Edge("SH",6));

        pque.offer(new Edge("WH",9));

        pque.offer(new Edge("CQ",1));

        while(!pque.isEmpty())

        {

            Edge e= pque.poll();

            System.out.println(e.to+", "+e.w);

        }

    }

}

import java.util.*;

class Edge{

    String to;

    int w;

    Edge(){}

    Edge(String to,int w)

    {

        this.to=to;

        this.w=w;

    }

}

class Comp implements Comparator<Edge>{

    public int compare(Edge e1,Edge e2)

    {

        return e1.w-e2.w;//由小到大排序

    }

}

public class Main{

    public static void main(String[] args){

        PriorityQueue<Edge> pque=new PriorityQueue(new Comp());

        pque.offer(new Edge("HJ",17));

        pque.offer(new Edge("HN",34));

        pque.offer(new Edge("NJ",12));

        while(!pque.isEmpty())

        {

            Edge e=pque.poll();

            System.out.println(e.to+", "+e.w);

        }

    }

}

import java.util.*;

class Edge{

    String to;

    int w;

    Edge(){}

    Edge(String to,int w)

    {

        this.to=to;

        this.w=w;

    }

}

public class Main{

    public static void main(String[] args){

        ArrayList<Edge>[] arc=new ArrayList[2];

        arc[0] = new ArrayList<Edge>();

        arc[0].add(new Edge("HJ",28));

        arc[0].add(new Edge("SH",21));

        arc[1] = new ArrayList<Edge>();

        arc[1].add(new Edge("NJ",12));

        arc[1].add(new Edge("SZ",19));

        for(int i=0;i<arc.length;i++)

        {

            for(int j=0;j<arc[i].size();j++)

            {

                Edge e=arc[i].get(j);

                System.out.print(e.to+", "+e.w+"  ");

            }

            System.out.println();

        }

    }

}