anagrams2.java

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

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);
                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);
    }
}