【每日一题0707】圣诞树

请实现一个函数,接收一个0~100内的整数n,返回一颗高度为n,且每一层宽度相同的圣诞树。非*号部分使用空格填充。

例如:height=5时,返回:

    *    
   ***   
  *****  
 ******* 
********* 

题目难度:中等
题目来源:codewars

def xmas_tree(height):
    pass

assert xmas_tree(1) == '*'
assert xmas_tree(3) == '  *  \n *** \n*****'
assert xmas_tree(5) == '    *    \n   ***   \n  *****  \n ******* \n*********'
def xmas_tree(height):
    tree = ""
    for i in range(height):
        for j in range(height*2 - 1):
            if (height+i) > j >= (height-i-1):
                tree += "*"
            else:
                tree += " "
        tree += "\n"
    return tree[:-1]

# print(xmas_tree(5))
assert xmas_tree(1) == '*'
assert xmas_tree(2) == ' * \n***'
assert xmas_tree(5) == '    *    \n   ***   \n  *****  \n ******* \n*********'
def xmas_tree(height):
    tree = ""
    for i in range(height):
        for j in range(height*2 - 1):
            if  abs(j - height) < i:
                tree += "*"
            else:
                tree += " "
        tree += "\n"
    return tree[:-1]

题解:

def xmas_tree(height):
    max_stars = height * 2 - 1
    line = []
    for i in range(1, height+1):
        stars_num = i*2-1
        blank_num = int((max_stars-stars_num)/2)
        line.append(('*' * stars_num).join([' '*blank_num]*2))

    return '\n'.join(line)

assert xmas_tree(1) == '*'
assert xmas_tree(3) == '  *  \n *** \n*****'
assert xmas_tree(5) == '    *    \n   ***   \n  *****  \n ******* \n*********'

:partying_face: :partying_face: :partying_face: :partying_face: :partying_face: :partying_face:

def xmas_tree(height):
    total = height - 1
    result = []
    for i in range(height):
        result.append(total * " " + (2*(i + 1)-1) * "*" + total * " ")
        total -= 1
    return "\n".join(result)


assert xmas_tree(1) == '*'
print(xmas_tree(5))
assert xmas_tree(3) == '  *  \n *** \n*****'
assert xmas_tree(5) == '    *    \n   ***   \n  *****  \n ******* \n*********'

肝!

def xmas_tree(num):
i = 1
while i <= num:
j = 1
temp=""
temp1=""
k=1
while k<=num-i:
temp1 += " "
k+=1
while j<=2i-1:
temp=temp+"
"
j+=1
print(temp1,temp)
i += 1
while 1:
num=int(input(“请输入一个整数n”))
xmas_tree(num)

感觉就是找规律啊,不知道对不对

def fn(n):
    res=''
    for i in range(n):
        if i<n-1:
            a=(' '*(n-i-1)+'*'*(2*i+1)+' '*(n-i-1)+'\n')
            res=res+a
        else:
            a=(' '*(n-i-1)+'*'*(2*i+1)+' '*(n-i-1))
            res=res+a
    return res

assert fn(5)=='    *    \n   ***   \n  *****  \n ******* \n*********'

@Amoyshmily 小佛老师 [’ '*blank_num]*2 此处为什么要×2 没理解

Hi。乘以2是因为这里操作的是空格,每一行是*号在中间,被左右两边的空格包围。所以每边的空格当成一个整体,一共是2个这样的空格整体。

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