View Code of Problem 53

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        for(int i = 1; i <= n; i ++) {
            for(int j = 1; j <= n - i; j ++) {
                System.out.print(" ");
            }
            for(int j = 1; j <=2 * i - 1; j ++) {
                System.out.print("*");
            }
            System.out.println();
        }

        for(int i = (2 * n + 1) / 2; i >= 1 ; i --) {
            for(int j = 1; j <= n - i; j ++) {
                System.out.print(" ");
            }
            for(int j = 1; j <=2 * i - 1; j ++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}