poj 4086:DNA排序

#include <iostream>
#include <map>
#include <fstream>
#include <algorithm>
#include <string>
using namespace std;

class Elem
{
public:
	int num;
	int order;
	string dna;
};



bool compare(Elem  a,Elem  b) 
{
	if(a.num < b.num)
		return true;
	else if( a.num == b.num && a.order < b.order )
		return true;
	else return false;
}


map<char,int> dnamap;
const int dna_length = 4;

void main_solution();
void read_data(string* & data,int &m);
int inversion( string & dna );
void initialize_map(map<char,int> &dnamap);



int main( )
{
	main_solution();
	system( "pause" );
	return 0;
}

void initialize_map(map<char,int> &dnamap)
{
	dnamap.insert( make_pair('A',0) );
	dnamap.insert( make_pair('C',1) );
	dnamap.insert( make_pair('G',2) );
	dnamap.insert( make_pair('T',3) );
}


// 求出dna字符串的逆序对
int inversion( string & dna )
{
	int num = 0;
	int now;
	int * dnahash = new int[ dna_length ];
	for(int i=0;i<dna_length;i++)
	{
		dnahash[i] = 0;
	}

	for( int i=0;i<dna.length();i++ )
	{
		now = dnamap.find( dna[i] )->second;
		dnahash[ now ] ++;
		for( int j = now+1; j<dna_length; j++ )
		{
			num += dnahash[j];
		}
	}
	return num ;
}

void read_data(string* & data,int &m)
{
	ifstream reader;
	reader.open("data.txt");
	reader>>m;
	reader>>m;
	data = new string[m];
	
	for( int i =0; i<m; i++ )
	{
		reader>>data[i];
	}
	reader.close();
}

void main_solution()
{
	string * data;
	int m;
	read_data(data,m);
	initialize_map(dnamap);
	Elem * myset = new Elem[m];
	for(int i=0;i<m;i++)
	{
		myset[i].dna = data[i];
		myset[i].order = i;
		myset[i].num = inversion(data[i]);
	}

	sort(myset,myset+m,compare);

	for(int i=0;i<m;i++)
		cout<<myset[i].dna<<endl;
}