贝壳笔试

import java.util.*;
public class Main {
    public static void main(String[] args) {


        Scanner scanner = new Scanner(System.in);
      //  int m = scanner.nextInt();
        int n = scanner.nextInt();
        String s2 = scanner.nextLine();
        String s = scanner.nextLine();
        StringBuilder sb = new StringBuilder();
        StringBuilder sb2 = new StringBuilder();

        int len = s.length();
        int i;
        int max=0;

        for (i = 0; i < len-1; i++) {
               sb.append(s.charAt(i));
               if (s.lastIndexOf(sb.toString())==len-1-i)
                   max=Math.max(max,i);
            }
        System.out.println(max);
        sb=new StringBuilder(s);
        for (int j=max+1;j<len;j++)
            sb2.append(s.charAt(j));
        for (int k=0;k<n-1;k++)
            sb.append(sb2.toString());
        System.out.println(sb.toString());

        }
}