题解 | DNA序列

#include <iostream>
using namespace std;

int main() {
    string s;
    int n;

    while (cin >> s >> n) {
        if (n == s.size())
            cout << s << endl;
        int maxCount = 0;
        string maxStr = "";
        for (int i = 0; i < s.size() - n; i++) {
            string substr = s.substr(i, n);

            int sum = 0;
            for (int j = 0; j < n; j++) {
                if (substr[j] == 'C' || substr[j] == 'G') {
                    sum++;
                }
            }

            if (sum > maxCount) {
                maxCount = sum;
                maxStr = substr;
            }
        }

        cout << maxStr << endl;
    }

}