Solve http://poj.org/problem?id=1007

DNASorting.java

import java.util.*;

public class DNASorting {
    public static class DNA implements Comparable {
        String dna;

        public DNA(String str) {
            dna = str;
        }

        public int compareTo(Object o) {
            return score() - ((DNA) o).score();
        }

        public int score() {
            int score = 0;
            for(int i = 0; i < dna.length(); i++) {
                for(int j = i + 1; j < dna.length(); j++) {
                    if(dna.charAt(j) < dna.charAt(i)) {
                        score++;
                    }
                }
            }
            return score;
        }
    }

    public static void main(String args[]) {
//
        Scanner scanner = new Scanner(System.in);
        String tokens[] = scanner.nextLine().split(" ");
        int L = Integer.parseInt(tokens[0]);
        int T = Integer.parseInt(tokens[1]);

        List<DNA> dnaList = new ArrayList<DNA>();
        for(int i = 0; i < T; i++) {
            dnaList.add(new DNA(scanner.nextLine()));
        }

        Collections.sort(dnaList);

        for(DNA dna : dnaList) {
            System.out.println(dna.dna);
        }
//        System.out.println(new DNA("AACEDGG").score());
    }

}