https://www.acmicpc.net/problem/2446

별 찍기 - 9.java

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        for (int i=0; i<2*n-1; i++){
            if (i<n){
                for (int j=0; j<i; j++)
                    System.out.print(" ");
                for (int j=0; j<(n-i)*2-1; j++)
                    System.out.print("*");
                System.out.println();
            }else{
                for (int j=0; j<2*(n-1)-i; j++)
                    System.out.print(" ");
                for (int j=0; j<(i+1-n)*2+1; j++)
                    System.out.print("*");
                System.out.println();
            }
        }
    }
}