HR자바 Java Priority Queue

개요

HR자바 Java Priority Queue

• https://www.hackerrank.com/challenges/java-priority-queue/problem
• 참고: 자바 PriorityQueue

해커랭크 Java

#	문제	비고
HR자바 Data Structures e
28	HR자바 Java 1D Array
29	HR자바 Java 2D Array
30	HR자바 Java Subarray
31	HR자바 Java Arraylist
32	HR자바 Java 1D Array (Part 2)
33	HR자바 Java List
34	HR자바 Java Map
35	HR자바 Java Stack
36	HR자바 Java Hashset
37	HR자바 Java Generics
38	HR자바 Java Comparator
39	HR자바 Java Sort
40	HR자바 Java Dequeue
41	HR자바 Java BitSet
42	HR자바 Java Priority Queue

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import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

import java.util.PriorityQueue;
/*
 * Create the Student and Priorities classes here.
 */
class Student implements Comparable<Student> {
    private int id;
    private String name;
    private double cgpa;
    public Student(int id, String name, double cgpa) {
        this.id = id;
        this.name = name;
        this.cgpa = cgpa;
    }
    public int getId() {
        return id;
    }
    public String getName() {
        return name;
    }
    public double getCgpa() {
        return cgpa;
    }
    public int compareTo(Student s) {
        int c;
        c = Double.valueOf(this.cgpa).compareTo(s.getCgpa());
        if( c != 0 ) return -c;
        c = this.name.compareTo(s.getName());
        if( c != 0 ) return c;
        return s.getId() - this.id;
    }
}

class Priorities {
    public List<Student> getStudents(List<String> events) {
        PriorityQueue<Student> q = new PriorityQueue<Student>();
        for(String event : events){
            if(event.equals("SERVED")) {
                q.poll();
                continue;
            }
            String[] temp = event.split(" ");
            String name = temp[1];
            double cgpa = Double.valueOf(temp[2]);
            int id = Integer.valueOf(temp[3]);
            q.add(new Student(id,name,cgpa));
        }
        List<Student> list = new ArrayList<Student>();
        while( !q.isEmpty() ) {
            list.add( q.remove() );
        }
        return list;
    }
}

public class Solution {
    private final static Scanner scan = new Scanner(System.in);
    private final static Priorities priorities = new Priorities();
    
    public static void main(String[] args) {
        int totalEvents = Integer.parseInt(scan.nextLine());    
        List<String> events = new ArrayList<>();
        
        while (totalEvents-- != 0) {
            String event = scan.nextLine();
            events.add(event);
        }
        
        List<Student> students = priorities.getStudents(events);
        
        if (students.isEmpty()) {
            System.out.println("EMPTY");
        } else {
            for (Student st: students) {
                System.out.println(st.getName());
            }
        }
    }
}