public class ChristmasTree {
    public static void main(String[] args) {
        int height = 5; // 圣诞树的高度
        printChristmasTree(height);
    }

    public static void printChristmasTree(int height) {
        printTree(height, height - 1, 1);
    }

    private static void printTree(int height, int spaces, int stars) {
        if (height == 0) {
            return;
        }

        printSpaces(spaces);
        printStars(stars);
        System.out.println();

        printTree(height - 1, spaces - 1, stars + 2);
    }

    private static void printSpaces(int count) {
        for (int i = 0; i < count; i++) {
            System.out.print(" ");
        }
    }

    private static void printStars(int count) {
        for (int i = 0; i < count; i++) {
            System.out.print("*");
        }
    }
}