Это я тестовое задание делала.. времени много ушло и гуглом пользовалась, поэтому не думаю что живое интервью потяну.
Однако любопытство гложет, что можно переписать, улучшить и почему?
http://www.codeshare.io/OR9al
package Interview;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Scanner;
import java.util.Collections;
import java.util.Comparator;
import java.util.LinkedList;
import java.util.Map;
/*
Write a function that takes two parameters:
(1) a String representing a text document and (2) an integer providing the number of items to return.
Implement the function such that it returns a list of Strings ordered by word frequency,
the most frequently occurring word first.
Use your best judgement to decide how words are separated.
Your solution should run in O(n) time where n is the number of characters in the document.
Implement this function as you would for a production/commercial system. You may use any standard data structures.
*/
//case sensitive e.g 'fish' is not the same as 'Fish'
public class Evernote {
public List<String> frequentWords(String docPath, int numOfItems)
{
Map<String, Integer>unsortedMap = new HashMap<String,Integer>();
List<String> freqWords=null;
List<String> allWords=new ArrayList<String>();
File f = new File (docPath);
Scanner scan =null;
try
{
scan = new Scanner(f);
while (scan.hasNext()){
allWords.add(scan.next());
}
for (int i = 0;i<allWords.size();i++)
{
if (unsortedMap.containsKey(allWords.get(i)))
{
unsortedMap.put(allWords.get(i), (unsortedMap.get(allWords.get(i)))+1);//word and increment occurrence
}
else
{
unsortedMap.put(allWords.get(i),1);//word and occurence 1
}
}
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
if (scan!=null)
{
scan.close();
}
}
//2. Sort Map
Map<String, Integer> sortedMap = sortByComparator(unsortedMap);
//2A. optional
//printMap(sortedMap);
//3. Save entire list of ordered keys
freqWords = new ArrayList<String>(sortedMap.keySet());//map should be ordered by value at this point
if (numOfItems>freqWords.size())
{
System.out.println("Number of requested frequent words("+numOfItems+") is greated than total number of frequent words("+freqWords.size()+")");
System.out.println("Returning entire list of frequent words");
}
else if ( numOfItems==0)
{
System.out.println("Number of requested frequent words is "+numOfItems);
freqWords=null;
}
else
{
freqWords=freqWords.subList(0, numOfItems);//return specific num of items
}
return freqWords;
}
private static Map<String, Integer> sortByComparator(Map<String, Integer> unsortMap) {
// Convert Map to List
List<Map.Entry<String, Integer>> list =
new LinkedList<Map.Entry<String, Integer>>(unsortMap.entrySet());
// Sort list with comparator, to compare the Map values
Collections.sort(list, new Comparator<Map.Entry<String, Integer>>() {
public int compare(Map.Entry<String, Integer> o1,
Map.Entry<String, Integer> o2) {
return (o1.getValue()).compareTo(o2.getValue());
}
});
// Convert sorted map back to a Map
Map<String, Integer> sortedMap = new LinkedHashMap<String, Integer>();
for (Iterator<Map.Entry<String, Integer>> it = list.iterator(); it.hasNext();) {
Map.Entry<String, Integer> entry = it.next();
sortedMap.put(entry.getKey(), entry.getValue());
}
return sortedMap;
}
public static void printMap(Map<String,Integer> sortedMap)
{
for (Map.Entry<String, Integer> entry : sortedMap.entrySet()) {
System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}
}
}
class TestEvernote
{
public static void main(String[] args) {
String path ="C:\\InterviewPractice\\words.txt";
Evernote ev = new Evernote();
List<String>freqWords =ev.frequentWords(path, 700);
for (String s: freqWords)
{
System.out.println(s);
}
}
}
