题解 | #DNA序列#

暴力法，遍历找就可以了

#include <algorithm>

using namespace std;

int main() {
    string str;
    while(getline(cin,str)){
        int k;
        cin>>k;
        int n = str.size();
        int max = -1,start = 0,cnt = 0;
        string temp;
        int i;
        for( i = 0;i<n-k;i++){
            
            for(int j = i;j<i+k;j++){
                if(str[j]=='C'||(str[j]=='G')){
                    cnt++;
                }
            }//innerfor
            if(cnt>max){
                max = cnt;
                start = i;
            }
            cnt = 0;
        }
        temp = str.substr(start,k);
        cout<<temp<<endl;
        
    }
}