POJ 1007 解题报告 DNA Sorting

#include <iostream>
#include <string>
#include <map>

using namespace std;

class DNA{
public:
string strDNA;
DNA(string);
};

DNA::DNA(string s)
{
strDNA = s;
}

int calculateInversionsNum(const string&);
bool operator<(const DNA&, const DNA&);

int main ()
{
string str;

int iNum;
int iLength;

cin >> iLength >> iNum;

map<DNA, int> mDna;

while (iNum--)
{
cin >> str;
DNA d = DNA(str);
++mDna[d];
}

map<DNA, int>::iterator iterI = mDna.begin();
while(iterI != mDna.end())
{
while (iterI->second --)
{
cout << iterI->first.strDNA << endl;
}
iterI ++;
}

return 0;
}

bool operator<(const DNA& dL, const DNA& dR)
{
if(calculateInversionsNum(dL.strDNA) < calculateInversionsNum(dR.strDNA))
{
return true;
}
else
{
return false;
}
}

int calculateInversionsNum(const string& str)
{
int i = 0;
int iInversionsNum = 0;
while (i < str.size() - 1)
{
int iCountRepeat = 1;
while (str[i] == str[i + 1])
{
iCountRepeat ++;
i++;
if (i == str.size() - 1)
{
return iInversionsNum;
}
}

int j = i;
int iAdd = 0;
while (j < str.size())
{
if (str[i] > str[j])
{
iAdd ++;
}
j ++;
}
iInversionsNum += iCountRepeat * iAdd;
i ++;
}
return iInversionsNum;
}