POJ 1007 DNA Sorting

DNA Sorting

Time Limit: 1000MS Memory Limit: 10000KTotal Submissions: 89359 Accepted: 35910

Description

One measure of ``unsortedness'' in a sequence is the number of pairs of entries that are out of order with respect to each other. For instance, in the letter sequence ``DAABEC'', this measure is 5, since D is greater than four letters to its right and E is greater than one letter to its right. This measure is called the number of inversions in the sequence. The sequence ``AACEDGG'' has only one inversion (E and D)---it is nearly sorted---while the sequence ``ZWQM'' has 6 inversions (it is as unsorted as can be---exactly the reverse of sorted). 

You are responsible for cataloguing a sequence of DNA strings (sequences containing only the four letters A, C, G, and T). However, you want to catalog them, not in alphabetical order, but rather in order of ``sortedness'', from ``most sorted'' to ``least sorted''. All the strings are of the same length. 

Input

The first line contains two integers: a positive integer n (0 < n <= 50) giving the length of the strings; and a positive integer m (0 < m <= 100) giving the number of strings. These are followed by m lines, each containing a string of length n.

Output

Output the list of input strings, arranged from ``most sorted'' to ``least sorted''. Since two strings can be equally sorted, then output them according to the orginal order.

Sample Input

10 6AACATGAAGGTTTTGGCCAATTTGGCCAAAGATCAGATTTCCCGGGGGGAATCGATGCAT

Sample Output

CCCGGGGGGAAACATGAAGGGATCAGATTTATCGATGCATTTTTGGCCAATTTGGCCAAA

        一样求逆序对数，根据逆序对数的数量稳定的排序（非递减），再输出DNA序列。依然是用归并排序，求逆序对数。

import java.util.Arrays;import java.util.Scanner;/** * Created by 小粤 on 2015/8/4. */public class Main{    private static DNA[] dnas;    private static char[] characters = new char[50];    private static char[] aux = new char[50];    public static void sort(int lo, int hi, int dnasIndex)    {        if (lo >= hi)            return;        int mid = (lo + hi) / 2;        sort(lo, mid, dnasIndex);        sort(mid + 1, hi, dnasIndex);        merge(lo, mid, hi, dnasIndex);    }    private static void merge(int lo, int mid, int hi, int dnasIndex)    {        int i = lo, j = mid + 1;        for (int k = lo; k <= hi; k++)        {            aux[k] = characters[k];        }        for (int k = lo; k <= hi; k++)        {            if (i > mid)            {                characters[k] = aux[j++];            }            else if (j > hi)            {                characters[k] = aux[i++];            }            else if (aux[j] < aux[i])            {                characters[k] = aux[j++];                dnas[dnasIndex].counter += mid - i + 1;            }            else            {                characters[k] = aux[i++];            }        }    }    public static void main(String[] args)    {        Scanner scanner = new Scanner(System.in);        int lengthOfStrings = scanner.nextInt();        int numberOfStrings = scanner.nextInt();        dnas = new DNA[numberOfStrings]; // Oh, shit! Because of Arrays.sort()..        for (int i = 0; i < numberOfStrings; i++)        {            dnas[i] = new DNA();            dnas[i].string = scanner.next();            for (int j = 0; j < lengthOfStrings; j++)            {                characters[j] = dnas[i].string.charAt(j);            }            sort(0, lengthOfStrings - 1, i);        }        Arrays.sort(dnas);        for (DNA dna : dnas)        {            System.out.println(dna);        }    }}class DNA implements Comparable<DNA>{    public String string;    public int counter;    @Override    public int compareTo(DNA o)    {        return counter - o.counter;    }    @Override    public String toString()    {        return string;    }}