题解 | #箭形图案#

while True:
    try:
        num = int(input())
        a, b = num * 2, num
        for i in range(1, num * 2 + 2):  # 应输出num*2+1行
            if i <=  num + 1:  # 前半段+1
                print(" " * a + "*" * i)
                a -= 2
            else:  # 后半段
                a += 2
                print(" " * (a+2) + "*" * b)  # 每行之间是两个空格的差值
                b -= 1            
    except:
        break