카카오신입공채 코딩테스트 1차(JAVA)

KakaoTest4.java

package com.jacknie.doodle.kakao;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Queue;
import java.util.StringTokenizer;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.stream.Collectors;

public class KakaoTest4 {

	public static void main(String[] args) {
		System.out.println(getBusTime(1, 1, 5, new String[] {"08:00", "08:01", "08:02", "08:03"}));
		System.out.println(getBusTime(2, 10, 2, new String[] {"09:10", "09:09", "08:00"}));
		System.out.println(getBusTime(2, 1, 2, new String[] {"09:00", "09:00", "09:00", "09:00"}));
		System.out.println(getBusTime(1, 1, 5, new String[] {"00:01", "00:01", "00:01", "00:01", "00:01"}));
		System.out.println(getBusTime(1, 1, 1, new String[] {"23:59"}));
		System.out.println(getBusTime(10, 60, 45, new String[] {"23:59","23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59", "23:59"}));
	}

	static Time getBusTime(int n, int t, int m, String[] timetable) {
		
		List<Crew> todayCrewList = Arrays.stream(timetable)
				.map(Time::parse)
				.sorted()
				.map(Crew::new).collect(Collectors.toList());
		
		ShuttleBus shuttleBus = new ShuttleBus(n, t, m);
		Queue<Crew> waitingLine = new LinkedBlockingQueue<>();
		
		while (shuttleBus.isEnableService()) {
			Time busTime = shuttleBus.getBusTime();
			todayCrewList.stream()
				.filter(crew -> !crew.isLeft() && busTime.compareTo(crew.getWaitTime()) >= 0)
				.forEach(waitingLine::add);
			shuttleBus.pickUp(waitingLine);
		}
		
		if (shuttleBus.isFull()) {
			Crew lastCrew = todayCrewList.get(todayCrewList.size() - 1);
			Time lastCrewWaitTime = lastCrew.getWaitTime();
			lastCrewWaitTime.minusMinutes(1);
			return lastCrewWaitTime;
		}
		else {
			Time busTime = shuttleBus.getBusTime();
			busTime.minusMinutes(t);
			return busTime;
		}
	}
	
	static class ShuttleBus {
		
		private final int n;
		private final int t;
		private final int m;
		private final Time closeTime = Time.parse("23:59");
		private Time busTime = Time.parse("09:00");
		private int service;
		private List<Crew> crewList = new ArrayList<>();
		
		public ShuttleBus(int n, int t, int m) {
			this.n = n;
			this.t = t;
			this.m = m;
			this.service = 0;
		}

		public void pickUp(Queue<Crew> waitingLine) {
			crewList.clear();
			for (int i = 0; i < m; i++) {
				Crew crew = waitingLine.poll();
				if (crew != null) {
					crew.takeBus();
					crewList.add(crew);
				}
			}
			busTime.plusMinutes(t);
			service++;
		}
		
		public boolean isEnableService() {
			return n > service && busTime.compareTo(closeTime) <= 0;
		}
		
		public boolean isFull() {
			return crewList.size() >= m;
		}

		public Time getBusTime() {
			return Time.of(busTime);
		}

		@Override
		public String toString() {
			return "ShuttleBus [n=" + n + ", t=" + t + ", m=" + m + ", closeTime=" + closeTime + ", busTime=" + busTime
					+ ", service=" + service + ", crewList=" + crewList + "]";
		}
	}
	
	static class Crew {
		
		private final Time waitTime;
		private boolean left;

		public Crew(Time waitTime) {
			this.waitTime = waitTime;
		}

		public Time getWaitTime() {
			return Time.of(waitTime);
		}
		
		public void takeBus() {
			this.left = true;
		}

		public boolean isLeft() {
			return left;
		}

		@Override
		public String toString() {
			return waitTime.toString();
		}
		
	}
	
	static class Time implements Comparable<Time> {
		
		private int hours;
		private int minutes;
		
		public static final Time of(Time other) {
			return new Time(other.hours, other.minutes);
		}
		
		public static final Time parse(String expression) {
			StringTokenizer tokenizer = new StringTokenizer(expression, ":");
			String hours = tokenizer.nextToken();
			String minutes = tokenizer.nextToken();
			return new Time(Integer.parseInt(hours), Integer.parseInt(minutes));
		}
		
		private Time(int hours, int minutes) {
			this.hours = hours;
			this.minutes = minutes;
		}
		
		public void plusMinutes(int t) {
			int mins = t + this.minutes;
			this.hours += mins / 60;
			this.minutes = mins % 60;
			if (this.hours >= 24) {
				throw new IllegalStateException("하루가 지났습니다.");
			}
		}
		
		public void minusMinutes(int t) {
			this.minutes -= t;
			if (this.minutes < 0) {
				int mins = this.minutes * -1;
				int remainder = mins % 60;
				this.hours -= mins / 60 + (remainder > 0 ? 1 : 0);
				this.minutes = remainder > 0 ? 60 - remainder : remainder;
			}
			if (this.hours < 0) {
				throw new IllegalStateException("하루 전입니다.");
			}
		}

		@Override
		public String toString() {
			return String.format("%02d:%02d", hours, minutes);
		}

		@Override
		public int compareTo(Time other) {
			if (other == null) {
				throw new NullPointerException("other 객체가 null 입니다.");
			}
			if (this.hours < other.hours) {
				return -1;
			}
			if (this.hours > other.hours) {
				return 1;
			}
			if (this.minutes < other.minutes) {
				return -1;
			}
			if (this.minutes > other.minutes) {
				return 1;
			}
			return 0;
		}
		
	}
}