题解 | #跟奥巴马一起编程(15)#

import java.util.*;
public class Main {
    
    public static void main(String[] args) {
        
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        char c = sc.next().charAt(0);
        int col = (int)Math.round(n*1.0/2);
        for(int i = 1 ; i <= col ; i++) {
            for(int j = 1 ; j <= n ; j++) {
                if(i == 1 || i == col || j == 1 || j == n) {
                    System.out.print(c);
                } else {
                    System.out.print(" ");
                }
            }
            System.out.println();
        }
    }
}