WkRmLl - Online Java Compiler & Debugging Tool

/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;

class Interval {
    int start, end;
    String train, platform;

    Interval(int s, int e, String t, String p) {
        start = s;
        end = e;
        train = t;
        platform = p;
    }
}

class TrainPlatformManager {

    Map<String, TreeMap<Integer, Interval>> platformMap = new HashMap<>();
    Map<String, TreeMap<Integer, Interval>> trainMap = new HashMap<>();

    // Assign train to platform
    public boolean assignTrain(String train, String platform, int start, int end) {
        if (start >= end) return false;

        platformMap.putIfAbsent(platform, new TreeMap<>());
        TreeMap<Integer, Interval> pm = platformMap.get(platform);

        // conflict check
        Map.Entry<Integer, Interval> floor = pm.floorEntry(start);
        if (floor != null && floor.getValue().end > start) return false;

        Map.Entry<Integer, Interval> ceil = pm.ceilingEntry(start);
        if (ceil != null && end > ceil.getKey()) return false;

        Interval interval = new Interval(start, end, train, platform);
        pm.put(start, interval);

        trainMap.putIfAbsent(train, new TreeMap<>());
        trainMap.get(train).put(start, interval);

        return true;
    }

    // Platform + time -> train
    public String getTrainAtPlatform(String platform, int time) {
        TreeMap<Integer, Interval> pm = platformMap.get(platform);
        if (pm == null) return null;

        Map.Entry<Integer, Interval> e = pm.floorEntry(time);
        if (e == null || time >= e.getValue().end) return null;

        return e.getValue().train;
    }

    // Train + time -> platform
    public String getPlatformForTrain(String train, int time) {
        TreeMap<Integer, Interval> tm = trainMap.get(train);
        if (tm == null) return null;

        Map.Entry<Integer, Interval> e = tm.floorEntry(time);
        if (e == null || time >= e.getValue().end) return null;

        return e.getValue().platform;
    }
}
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
	}
}