算法：POJ1007 DNA sorting

这题比较简单，重点应该在如何减少循环次数。

package practice;

import java.io.BufferedInputStream;
import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;

/**
 * DNA sorting
 *
 * @author caiyu
 * @date 2014-11-5
 */
public class POJ1007 {
    public static void main(String[] args) {
        Scanner cin = new Scanner(new BufferedInputStream(System.in));
        int l = cin.nextInt();
        int t = cin.nextInt();

        String s;
        Map<Integer, String> m = new TreeMap<Integer, String>();
        for (int i = 0; i < t; i++) {
            s = cin.next();
            int[] count = new int[l];
            int inversion = 0;
            for (int j = 0, len = l - 1; j < len; j++) {
                count[j] = s.charAt(j);
                for (int h = 0; h < j; h++) {
                    if (count[h] > count[j])
                        inversion++;
                }
            }
            m.put(inversion, s);
        }

        for (String x : m.values()) {
            System.out.println(x);
        }
    }
}