题解 | #统计大写字母个数#

import java.util.*;

public class Main{
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        while (scan.hasNext()) {
            String data = scan.nextLine();
            int len = Integer.parseInt(scan.nextLine());
            double max = 0.0;
            String result = "";
            for (int i = 0; i < data.length() - len + 1; i++) {
                String str = data.substring(i, len + i);
                String str2 = str.replaceAll("[^CG]", "");
                double x = str2.length() * 1.0 / str.length();
                if (x > max) {
                    result = str;
                    max = x;
                    if (x == 1.0) {
                        break;
                    }
                }
            }
            System.out.println(result);
        }
    }
}