Facebook Hacker Cup 2013 Qualification Round Beautiful Strings Java

BeautifulStrings.java

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;

/**
 * @author psy
 * 
 */
public class BeautifulStrings {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		List<String> output = new LinkedList<String>();

		BeautyCounter beautyCounter = new BeautyCounter();

		int strings = Integer.parseInt(in.nextLine());

		for (int i = 1; i <= strings; i++) {
			String string = in.nextLine();
			int result = beautyCounter.count(string);

			output.add("Case #" + i + ": " + result);
		}

		for (String out : output) {
			System.out.println(out);
		}

	}

	private static class BeautyCounter {

		private CharComparator comparator = new CharComparator();

		public int count(String string) {

			// to lower
			String preppedString = string.toLowerCase(Locale.US);
			Map<Character, Integer> chars = new HashMap<Character, Integer>();

			// filter characters
			for (int i = 0; i < preppedString.length(); i++) {
				Character character = preppedString.charAt(i);

				if (Character.isLetter(character)) {

					if (!chars.containsKey(character)) {
						chars.put(character, 0);
					}

					chars.put(character, chars.get(character) + 1);
				}
			}

			return doCount(chars);
		}

		private int doCount(Map<Character, Integer> chars) {

			if (chars.size() > 26) {
				throw new IllegalArgumentException("more than 26 characters given");
			}

			List<Entry<Character, Integer>> sortedChars = new ArrayList<Entry<Character, Integer>>(chars.entrySet());

			Collections.sort(sortedChars, comparator);

			int sum = 0;
			int beautyIndex = 26;

			for (Entry<Character, Integer> entry : sortedChars) {
				sum += beautyIndex * entry.getValue();
				beautyIndex--;
			}

			return sum;
		}

		private static class CharComparator implements Comparator<Map.Entry<Character, Integer>> {

			public int compare(Entry<Character, Integer> o1, Entry<Character, Integer> o2) {

				return o2.getValue().compareTo(o1.getValue());
			}

		}

	}

}