Program.java

package com.google.hashcode.tek2d;

import com.google.hashcode.tek2d.model.*;

import java.io.*;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

/**
 * Created by gmardon on 23/02/2017.
 */
public class Program {
    public static void main(String[] args) throws FileNotFoundException {
        while(true)
            new Program().process("input/trending_today.in");

    }

    public void process(String filePath) throws FileNotFoundException {
        File file = new File(filePath);
        List<Video> videos = new LinkedList<>();
        LinkedList<CacheServer> cacheServers = new LinkedList<>();
        List<Endpoint> endpoints = new LinkedList<>();

        Scanner scanner = new Scanner(file);

        int videosCount = scanner.nextInt();
        int endpointsCount = scanner.nextInt();
        int requestsCount = scanner.nextInt();
        int cacheServersCount = scanner.nextInt();
        int cacheSize = scanner.nextInt();

        System.out.println("Videos count : " + videosCount);
        System.out.println("Endpoints count : " + endpointsCount);
        System.out.println("Requests count : " + requestsCount);
        System.out.println("Cache servers : " + cacheServersCount);
        System.out.println("Cache size : " + cacheSize + "MB");

        for (int i = 0; i < videosCount; i++) {
            Video video = new Video(i, scanner.nextInt());
            videos.add(video);
        }

        for (int i = 0; i < endpointsCount; i++) {
            Endpoint endpoint = new Endpoint(i, scanner.nextInt());
            ArrayList<CacheLink> cacheLinks = new ArrayList<>();
            int cachesCount = scanner.nextInt();
            for (int y = 0; y < cachesCount; y++) {
                int id = scanner.nextInt();
                int latency = scanner.nextInt();
                if (!cacheServers.stream().filter(s -> s.getId() == id).findFirst().isPresent()) {
                    cacheServers.add(new CacheServer(id, cacheSize));
                }
                CacheLink link = new CacheLink(latency, cacheServers.stream().filter(s -> s.getId() == id).findFirst().get(), endpoint);
                cacheServers.stream().filter(s -> s.getId() == id).findFirst().get().getLinks().add(link);
                cacheLinks.add(y, link);
            }
            endpoint.setLinks(cacheLinks);
            endpoints.add(endpoint);
        }

        for (int i = 0; i < requestsCount; i++) {
            int videoId = scanner.nextInt();
            int endpointId = scanner.nextInt();
            int requests = scanner.nextInt();

            Endpoint endpoint = endpoints.stream().filter(s -> s.getId() == endpointId).findFirst().get();
            Video video = videos.stream().filter(s -> s.getId() == videoId).findFirst().get();
            endpoint.getRequests().add(new RequestGroup(requests, video));
        }

        // end of parsing

        for (CacheServer server : cacheServers) {
            LinkedList<Video> videosBySize = server.getVideosBySize();

            LinkedList<Video> remain = videosBySize.stream().filter(v -> v.getSize() < server.getMaxSize() - server.getActualSize()).collect(Collectors.toCollection(LinkedList::new));
            while (!remain.isEmpty()) {
                int id = (int) (Math.random() * remain.size());
                videosBySize.remove(id);
                server.getVideos().add(remain.get(id));
                remain = videosBySize.stream().filter(v -> v.getSize() < server.getMaxSize() - server.getActualSize()).collect(Collectors.toCollection(LinkedList::new));
            }
        }
        long total = 0;
        for (Endpoint endpoint : endpoints) {
            for (RequestGroup group : endpoint.getRequests()) {
                CacheLink best = null;
                for (CacheLink link : endpoint.getLinks()) {
                    if (link.getCache().getVideos().contains(group.getVideo())) {
                        if (best == null)
                            best = link;
                        if (link.getLatency() < best.getLatency())
                            best = link;
                    }
                }
                if (best != null)
                    total += (endpoint.getLatency() - best.getLatency()) * group.getSize();
            }
        }
      //  if (total > best_total)
            dump(filePath + ".out", cacheServers);

      //  System.out.println("total: " + total);

      //  return (total > best_total) ? total : best_total;
    }

    public void dump(String path, LinkedList<CacheServer> servers) {
        Writer writer = null;

        try {
            writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(path), "utf-8"));
            writer.write(servers.size() + "\n");
            for (CacheServer server : servers) {
                writer.write(server.getId() + " ");
                for (Video video : server.getVideos()) {
                    writer.write(video.getId() + " ");
                }
                writer.write("\n");
            }
        } catch (IOException ex) {
            // report
        } finally {
            try {
                writer.close();
            } catch (Exception ex) {/*ignore*/}
        }
    }
}