DNA序列 (HJ63)

#include <iostream>
#include <string>

using namespace std;


int main()
{
    string s = "";
    int n = 0;

    while (cin >> s >> n)
    {
        string maxString = "";
        int maxCount = 0;

        if (n == s.size()) maxString = s;

        for (int i = 0; i < s.size() - n; i++)
        {
            int j = i;
            int len = j + n;
            float count = 0;

            for (;j < len;j++)
            {
                if (s[j] == ‘C‘ || s[j] == ‘G‘)
                {
                    count++;
                }
            }
            
            if (count > maxCount)
            {
                maxCount = count;
                maxString = s.substr(i, n);
            }
        }

        cout << maxString << endl;
    }

    return 0;
}