https://www.acmicpc.net/problem/2523

별 찍기 - 13.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=1; i<=2*n-1; i++){
            if (i<=n){
                for(int j=0; j<i; j++)
                    System.out.print("*");
                System.out.println();
            }else{
                for(int j=0; j<2*n-i; j++)
                    System.out.print("*");
                System.out.println();
            }
        }
    }
}