Java集合创建Anagrams算法

import java.util.*;

import java.io.*;
/* from 
时代Java公众号 - nowjava.com*/


public class Anagrams2 {

    public static void main(String[] args) {

        int minGroupSize = Integer.parseInt(args[1]);


        // Read words from file and put into simulated multimap

        Map<String, List<String>> m = new HashMap<String, List<String>>();

        try {

            Scanner s = new Scanner(new File(args[0]));

            while (s.hasNext()) {

                String word = s.next();

                String alpha = alphabetize(word);/** 来 自 nowjava - 时代Java**/

                List<String> l = m.get(alpha);

                if (l == null)

                    m.put(alpha, l = new ArrayList<String>());

                l.add(word);

            }

        } catch (IOException e) {

            System.err.println(e);

            System.exit(1);

        }


        // Make a List of all permutation groups above size threshold

        List<List<String>> winners = new ArrayList<List<String>>();

        for (List<String> l : m.values())

            if (l.size() >= minGroupSize)

                winners.add(l);


        // Sort permutation groups according to size

        Collections.sort(winners, new Comparator<List<String>>() {

            public int compare(List<String> o1, List<String> o2) {

                return o2.size() - o1.size();

            }

        });


        // Print permutation groups

        for (List<String> l : winners) {

            System.out.println(l.size() + ": " + l);

        }

    }


    private static String alphabetize(String s) {

        char[] a = s.toCharArray();

        Arrays.sort(a);

        return new String(a);

    }

}