题解 | #DNA序列#

#include <iostream>
using namespace std;

int main() {
   string str;
   int n;
   cin>>str>>n;
   int m = str.size();
   int num = 0;
   int left = 0;
   int right = 0;
   int cut = 0;
   int count = 0;
   for(int i=0;i<m;i++)
   {
        left = i;
        while(right-left<n)
        {
            if(str[right]=='C'||str[right]=='G')count++;
            right++;
        }
        if(count>num)
        {
            cut = left;
            num = count;
        }
        if(str[left]=='C'||str[left]=='G') count--;

   }
   for(int j=cut;j<cut+n;j++)cout<<str[j];
   cout<<endl;
   return 0;
}
// 64 位输出请用 printf("%lld")