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‎Homework 1/Edison Ponari - Homework 1 Report.pdf

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‎Homework 1/src/Exercise 1 - MultithreadedSearch/MultithreadedSearch.java

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import java.io.File;
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import java.io.FileNotFoundException;
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import java.util.*;
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import java.util.concurrent.CyclicBarrier;
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import java.util.concurrent.locks.Lock;
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import java.util.concurrent.locks.ReentrantLock;
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public class MultithreadedSearch {
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//keyword to be searched in each file.
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static String wordSearched;
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//path of each one of the files to search.
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static ArrayList<String> filesSearched = new ArrayList<>();
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//total occurrences of the word in every file.
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static int totalOccurrences = 0;
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//option to change the execution.
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static boolean liveResults = false;
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public static void main(String[] args) throws InterruptedException {
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//first argument is the word to be searched.
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//cast to lower case to make the searching easier.
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wordSearched = args[0].toLowerCase();
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//process each argument from the second to the last.
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for(int i=1;i<(args.length);i++){
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//if the user used the option -liveResults, change the static variable of this class.
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if(args[i].equals("-liveResults")){
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liveResults = true;
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continue;
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}
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//store all file names.
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filesSearched.add(args[i]);
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}
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//create a array of threads to search for the word we need to find.
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SearchingThread[] threadsToSearch = new SearchingThread[filesSearched.size()];
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//if liveResult is selected as a option, print the live results.
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if(liveResults){
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System.out.println("LIVE RESULTS:\n");
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}
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for(int i=0;i<filesSearched.size();i++){
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//create and start each thread.
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threadsToSearch[i] = new SearchingThread(filesSearched.get(i));
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threadsToSearch[i].start();
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}
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//join all the threads.
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for(Thread thread:threadsToSearch){
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thread.join();
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}
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//print the summary.
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System.out.println("\nTHE SUMMARY:\n");
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//each thread is printed in parallell to each other.
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Thread[] printThreads = new Thread[filesSearched.size()];
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for(int i=0;i<filesSearched.size();i++){
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//create and start threads to print the result of each thread.
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printThreads[i] = new PrintableThread(threadsToSearch[i]);
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printThreads[i].start();
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}
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for(Thread thread:printThreads){
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//join the printing threads.
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thread.join();
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}
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//print final result.
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System.out.println("\nTOTAL: "+totalOccurrences+" occurrence"+(totalOccurrences>1?"s":"")+" of keyword "+wordSearched);
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}
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//class to print threads' data in parallel.
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static class PrintableThread extends Thread{
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//thread to be printed.
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private final SearchingThread thread;
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//constructor
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PrintableThread(SearchingThread thread){
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this.thread = thread;
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}
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//override the run method to be run in parallel.
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@Override
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public void run(){
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//print the thread data.
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System.out.println(thread);
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}
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}
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//class to search a word in a file in parallel.
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static class SearchingThread extends Thread{
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//path of the file the thread is searching in.
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private final String path_file;
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//total occurrences of the word in the file.
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private int total=0;
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//constructor.
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SearchingThread(String path_file){
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this.path_file = path_file;
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}
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@Override
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public void run(){
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//try to open the file.
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try {
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//scanner for the file.
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Scanner fileInput = new Scanner(new File(path_file));
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//keep note of the number of lines of the file.
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int lineNum=0;
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while(fileInput.hasNext()){
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//count lines.
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lineNum++;
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//get the next line from the file.
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//cast to lowercase to make it easier to search the pattern.
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String line = fileInput.nextLine().toLowerCase();
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//linear search in the line for the word.
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for(int i=0;i<line.length()-wordSearched.length()+1;i++){
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if(line.substring(i,i+wordSearched.length()).equals(wordSearched)){
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total++;
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//print the live result.
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if(liveResults){
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System.out.println(countOccurrence(lineNum));
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}
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}
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}
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}
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//lock the totalOccurrences variable to add and then unlock.
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synchronized (this) {
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totalOccurrences += total;
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}
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}
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catch (FileNotFoundException e) {
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e.printStackTrace();
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}
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}
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//print the live result.
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public String countOccurrence(int line){
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return path_file+":\t"+total+" "+"occurrence"+(total>1?"s":"") + " at line "+line;
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}
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//print the data of the thread.
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@Override
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public String toString(){
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return path_file+":\t"+total+" "+"occurrence"+(total>1?"s":"");
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}
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}
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}

‎Homework 1/src/Exercise 1 - MultithreadedSearch/file1.txt

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In the time since the end of communism and isolationism, Albania has extended its responsibilities and position in
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continental and international affairs, developing and establishing friendly relations with other countries around the
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world. The country's foreign policy priorities are its accession into the European Union (EU), the international
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recognition of Kosovo and the expulsion of Cham Albanians, as well as helping and protecting the rights of the Albanians
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in Kosovo, Montenegro, North Macedonia, Greece, Serbia, Italy and the Diaspora.[172]
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Albania's admission into the North Atlantic Treaty Organisation (NATO) was considered by Albanian politicians
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to be a significant ambition for the country's foreign policy. The country has been extensively engaged with the
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NATO and has maintained its position as a stability factor and a strong ally of the United States and the European
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Union (EU) in the region of the Balkans. Albania maintains strong ties with the United States ever after it supported
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the Albania's independence and democracy.[173] Nowadays, both countries have signed a number of agreements and treaties.
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In 2007, Albania welcomed George W. Bush who became the first President of the United States ever to visit the country.
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Albania and Kosovo are culturally, socially and economically very closely rooted due to the Albanian majority
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population in Kosovo. In 1998, the country contributed in supporting allied efforts to end the humanitarian
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tragedy in Kosovo and secure the peace after the NATO bombing of Yugoslavia.
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Albania has been an active member of the United Nations since 1955. They country took on membership for the United
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Nations Economic and Social Council from 2005 to 2007 as well as in 2012.[174] It served as vice president of the
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ECOSOC in 2006 and 2013.[174] In 2014, it also joined the United Nations Human Rights Council from 2015 to 2017 and
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was elected vice president in 2015.[175] Albania is a full member of numerous international organisations inclusively
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the Council of Europe, International Organisation for Migration, World Health Organization, Union for the Mediterranean,
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Organisation of Islamic Cooperation, Organization for Security and Co-operation in Europe, International Monetary Fund,
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World Trade Organization and La Francophonie.

‎Homework 1/src/Exercise 1 - MultithreadedSearch/file2.txt

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Albania declared independence from the Ottoman Empire on 28 November 1912, accompanied with the establishment of the
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Senate and Government by the Assembly of Vlorë on 4 December 1912.[74][75][76][77] Its sovereignty was recognised by
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the Conference of London. On 29 July 1913, the Treaty of London delineated the borders of the country and its neighbors,
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leaving many Albanians outside Albania, predominantly partitioned between Montenegro, Serbia and Greece.[78]
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Headquartered in Vlorë, the International Commission of Control was established on 15 October 1913 to take care of the
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administration of newly established Albania, until its own political institutions were in order.[79][80] The International
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Gendarmerie was established as the first law enforcement agency of the Principality of Albania. In November, the first
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gendarmerie members arrived in the country. Prince of Albania Wilhelm of Wied (Princ Vilhelm Vidi) was selected as the
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first prince of the principality.[81] On 7 March, he arrived in the provisional capital of Durrës and started to organise
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his government, appointing Turhan Pasha Përmeti to form the first Albanian cabinet.
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In November 1913, the Albanian pro-Ottoman forces had offered the throne of Albania to the Ottoman war Minister of
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Albanian origin, Ahmed Izzet Pasha.[82] The pro-Ottoman peasants believed that the new regime was a tool of the six
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Christian Great Powers and local landowners, that owned half of the arable land.[83]
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In February 1914, the Autonomous Republic of Northern Epirus was proclaimed in Gjirokastër by the local Greek population
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against incorporation to Albania. This initiative was short-lived, and in 1921 the southern provinces were incorporated
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into the Albanian Principality.[84][85] Meanwhile, the revolt of Albanian peasants against the new Albanian regime erupted
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under the leadership of the group of Muslim clerics gathered around Essad Pasha Toptani, who proclaimed himself the savior
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of Albania and Islam.[86][87] In order to gain support of the Mirdita Catholic volunteers from the northern part of Albania,
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Prince Wied appointed their leader, Prênk Bibë Doda, to be the foreign minister of the Principality of Albania.
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In May and June 1914, the International Gendarmerie was joined by Isa Boletini and his men, mostly from Kosovo,[88]
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and northern Mirdita Catholics, were defeated by the rebels who captured most of Central Albania by the end of August
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1914.[89] The regime of Prince Wied collapsed, and he left the country on 3 September 1914.

‎Homework 1/src/Exercise 1 - MultithreadedSearch/file3.dat

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Albania declared independence from the Ottoman Empire on 28 November 1912, accompanied with the establishment of the
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Senate and Government by the Assembly of Vlorë on 4 December 1912.[74][75][76][77] Its sovereignty was recognised by
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the Conference of London. On 29 July 1913, the Treaty of London delineated the borders of the country and its neighbors,
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leaving many Albanians outside Albania, predominantly partitioned between Montenegro, Serbia and Greece.[78]
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Headquartered in Vlorë, the International Commission of Control was established on 15 October 1913 to take care of the
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administration of newly established Albania, until its own political institutions were in order.[79][80] The International
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Gendarmerie was established as the first law enforcement agency of the Principality of Albania. In November, the first
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gendarmerie members arrived in the country. Prince of Albania Wilhelm of Wied (Princ Vilhelm Vidi) was selected as the
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first prince of the principality.[81] On 7 March, he arrived in the provisional capital of Durrës and started to organise
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his government, appointing Turhan Pasha Përmeti to form the first Albanian cabinet.
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In November 1913, the Albanian pro-Ottoman forces had offered the throne of Albania to the Ottoman war Minister of
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Albanian origin, Ahmed Izzet Pasha.[82] The pro-Ottoman peasants believed that the new regime was a tool of the six
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Christian Great Powers and local landowners, that owned half of the arable land.[83]

‎Homework 1/src/Exercise 2 - ProbabilityEstimation/Java Multithreading/ProbabilityEstimation.java

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import java.util.concurrent.locks.Lock;
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import java.util.concurrent.locks.ReentrantLock;
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public class ProbabilityEstimation {
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//2 patterns we want to calculate the probability of appearing first.
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static String pattern1;
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static String pattern2;
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//default values for the number of trials and the number of threads used.
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static int trials = 1000000;
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static int threadsNum = 10;
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//total occurrences found from all the threads.
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static int pattern1Found = 0;
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static int pattern2Found = 0;
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public static void main(String[] args) throws InterruptedException {
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//get arguments from the args and depending on the length, process them.
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pattern1 = args[0];
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pattern2 = args[1];
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//if there is a third argument.
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if(args.length>2){
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trials = Integer.parseInt(args[2]);
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}
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//if there is a forth argument.
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if(args.length>3){
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threadsNum = Integer.parseInt(args[3]);
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}
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//create array of threads.
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Thread[] threads = new Thread[threadsNum];
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for(int i=0;i<threadsNum;i++){
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//create custom threads giving their rank as a property.
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threads[i] = new GenerateCoinFlips(i);
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//start each thread.
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threads[i].start();
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}
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//join each thread with the main thread.
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for(Thread thread:threads){
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thread.join();
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}
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//print the result.
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System.out.println("Estimated values with "+trials+" random experiments with "+threadsNum+" threads:");
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System.out.println("The probability that "+pattern1+" appears first is "+calculateProbability(pattern1Found));
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System.out.println("The probability that "+pattern2+" appears first is "+calculateProbability(pattern2Found));
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}
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//just to make sure the number of trials isn't 0.
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static double calculateProbability(int occurrences){
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return trials!=0?(double)occurrences/trials:0;
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}
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//class inheriting from Thread class.
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static class GenerateCoinFlips extends Thread{
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//Pattern generated by flipping coins to be compared to our patterns.
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private String patternGenerated = "";
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//rank to separate the work as evenly as possible.
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private final int rank;
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//number of locally found patterns by this thread.
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private int pattern1FoundHere = 0;
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private int pattern2FoundHere = 0;
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//constructor.
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GenerateCoinFlips(int rank){
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this.rank = rank;
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}
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//override the run method.
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@Override
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public void run(){
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//while the thread has not reached the number of trials.
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for(int i=rank;i<trials;){
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//generate a random H for heads and T for tails.
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String randomChar = ((int)(Math.random()*2) == 1) ? "H":"T";
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//concatenate the pattern it generated until now with the new "H":"T" char.
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patternGenerated = patternGenerated.concat(randomChar);
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//if the generated pattern ending matches with one of the patterns, increment its count and reset the pattern generated.
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if(patternGenerated.endsWith(pattern1)){
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pattern1FoundHere++;
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patternGenerated = "";
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//helps since i%threadNum = rank always.
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i+=threadsNum;
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}
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if(patternGenerated.endsWith(pattern2)){
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pattern2FoundHere++;
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patternGenerated = "";
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//helps since i%threadNum = rank always.
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i+=threadsNum;
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}
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}
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//synchronize this block to assure data integrity.
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synchronized (this) {
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pattern1Found += pattern1FoundHere;
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pattern2Found += pattern2FoundHere;
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}
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}
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}
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}

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