schedule_jia

Posted 2020-06-13

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class Scheduler2 {
	
	private static final int MAX_OVERLAPPED_CONTENTS = 3;

	public Scheduler2() {
		// TODO Auto-generated constructor stub
	}
	
	public static enum Type {
		start,
		end
	}
	
	public static class TimeNode {
		public static List<TimeNode> constructNodes(ScheduleRequest scheduleRequest, int index) {
			List<TimeNode> timeNodes = new ArrayList<>(2);
			timeNodes.add(new TimeNode(index, scheduleRequest.id, scheduleRequest.startTime, Type.start));
			timeNodes.add(new TimeNode(index, scheduleRequest.id, scheduleRequest.endTime, Type.end));
			return timeNodes;
		}
		private final int index;
		private final String id;
		private final int time;
		private final Type type;
		private TimeNode(int index, String id, int time, Type type) {
			this.index = index;
			this.id = id;
			this.time = time;
			this.type = type;
		}
		public int getIndex() {
			return index;
		}
		public String getId() {
			return id;
		}
		public int getTime() {
			return time;
		}
		public Type getType() {
			return type;
		}
		public final static Comparator<TimeNode> timeComparator = new Comparator<TimeNode>() {
			
			public int compare(TimeNode t1, TimeNode t2) {
				//TODO should compareTo do null check?
				if (t1.getTime() == t2.getTime()) {
					if (t1.getType() == Type.start) {
						return -1;
					}
					else {
						return 1;
					}
				}
				return t1.getTime() - t2.getTime();
			}			
		};


	}
	
	public static List<ScheduleRequest> schedule() {
		//TODO for 1 area only now
		List<ScheduleRequest> scheduleRequests = readCommercials();
		if (scheduleRequests == null || scheduleRequests.size() == 0) {
			return new ArrayList<ScheduleRequest>();
		}
		//split it into start end time
		List<TimeNode> timeNodes = new LinkedList<>();
		//TODO sort performance on LinkedList and ArrayList
		for (int i = 0; i < scheduleRequests.size(); i++) {
			if (scheduleRequests.get(i) != null) {
				timeNodes.addAll(TimeNode.constructNodes(scheduleRequests.get(i), i));
			}
		}
		//sort nodes according to time
		Collections.sort(timeNodes, TimeNode.timeComparator);
		List<ScheduleRequest> resultCommercials = new LinkedList<>();
		List<ScheduleRequest> toRemoveCommercials = new LinkedList<>();
		//TODO
		//a HashMap to maintain during scan, the String is the ID and the Integer is
		//the index of the Content in the Contents 
		Map<String, Integer> map = new HashMap<>();
		//scan the sorted timeNodes
		for (TimeNode node : timeNodes) {
			if (node.getType() == Type.start) {
				//this node represent a start time
				if (map.containsKey(node.getId())) {
					//id conflicts
					//TODO may change remove policy here
					//Remove policy: remove latest coming
					toRemoveCommercials.add(scheduleRequests.get(node.getIndex()));
				}
				else if (map.keySet().size() == MAX_OVERLAPPED_CONTENTS){
					//at current point the set of overlapped contents is oversized
					//TODO may change remove policy here
					toRemoveCommercials.add(scheduleRequests.get(node.getIndex()));
				}
				else {
					//this node is selected into this point
					resultCommercials.add(scheduleRequests.get(node.getIndex()));
				}
			}
			else {
				//this node represent an end time
				if (map.containsKey(node.getId()) && map.get(node.getId()) == node.index) {
					//the corresponded start time is actually in the map
					map.remove(node.id);
				}
			}
		}
		//Output
		IO.writeAds(resultCommercials);
		return null;
	}
	
	public static List<ScheduleRequest> readCommercials() {
		List<ScheduleRequest> list = new LinkedList<>();
		ScheduleRequest ad = null;
		while ((ad = IO.readAd()) != null) {
			list.add(ad);
		}
		return list;
	}

}