package Others;

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

/* display the most frequent K words in the file and the times it appear
 in the file – shown in order (ignore case and periods) */

public class TopKWords {
 static class CountWords {
 private String fileName;

 public CountWords(String fileName) {
 this.fileName = fileName;
 }

 public Map<String, Integer> getDictionary() {
 Map<String, Integer> dictionary = new HashMap<>();
 FileInputStream fis = null;

 try {

 fis = new FileInputStream(fileName); // open the file
 int in = 0;
 String s = ""; // init a empty word
 in = fis.read(); // read one character

 while (-1 != in) {
 if (Character.isLetter((char) in)) {
 s += (char) in; //if get a letter, append to s
 } else {
 // this branch means an entire word has just been read
 if (s.length() > 0) {
 // see whether word exists or not
 if (dictionary.containsKey(s)) {
 // if exist, count++
 dictionary.put(s, dictionary.get(s) + 1);
 } else {
 // if not exist, initiate count of this word with 1
 dictionary.put(s, 1);
 }
 }
 s = ""; // reInit a empty word
 }
 in = fis.read();
 }
 return dictionary;
 } catch (IOException e) {
 e.printStackTrace();
 } finally {
 try {
 // you always have to close the I/O streams
 if (fis != null)
 fis.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 return null;
 }
 }

 public static void main(String[] args) {
 // you can replace the filePath with yours
 CountWords cw = new CountWords("/Users/lisanaaa/Desktop/words.txt");
 Map<String, Integer> dictionary = cw.getDictionary(); // get the words dictionary: {word: frequency}

 // we change the map to list for convenient sort
 List<Map.Entry<String, Integer>> list = new ArrayList<>(dictionary.entrySet());

 // sort by lambda valueComparator
 list.sort(Comparator.comparing(
 m -> m.getValue())
 );

 Scanner input = new Scanner(System.in);
 int k = input.nextInt();
 while (k > list.size()) {
 System.out.println("Retype a number, your number is too large");
 input = new Scanner(System.in);
 k = input.nextInt();
 }
 for (int i = 0; i < k; i++) {
 System.out.println(list.get(list.size() - i - 1));
 }
 input.close();
 }
}