优先级队列

package com.bjwilly.test;

import java.util.PriorityQueue;

public class PriorityQueueTest extends PriorityQueue<PriorityQueueTest.TodoItem>{
    static class TodoItem implements Comparable<TodoItem>{
        private char primary;
        private int secondary;
        private String item;

        public TodoItem(String td, char pri, int sec){
            primary = pri;
            secondary = sec;
            item = td;
        }
        @Override
        public int compareTo(TodoItem arg) {
            if (primary > arg.primary)
                return + 1 ;
            if (primary == arg.primary)
                if (secondary > arg.secondary)
                    return + 1 ;
                else if (secondary == arg.secondary)
                    return 0 ;
            return - 1 ;
        }

        public String toString(){
            return Character.toString(primary)+ secondary + ": " + item;
        }

    }

    public void add(String td, char pri, int sec){
        super .add( new TodoItem(td,pri,sec));
    }
    public static void main(String[] args) {
        PriorityQueueTest toDoList = new PriorityQueueTest();
        toDoList.add( "Empty trash" , 'C' , 4 );
        toDoList.add( "Feed dog" , 'A' , 2 );
        toDoList.add( "Feed bird" , 'B' , 7 );
        toDoList.add( "Mow lawn" , 'C' , 3 );
        toDoList.add( "Water lawn" , 'A' , 1 );
        toDoList.add( "Feed cat" , 'B' , 1 );
        while (!toDoList.isEmpty())
            System.out.println(toDoList.remove());
    }
}

输出结果

A1: Water lawn
A2: Feed dog
B1: Feed cat
B7: Feed bird
C3: Mow lawn
C4: Empty trash

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