题解 | #超级圣诞树# 递归

先按规律处理好，放进ans数组，再把右侧多余的空格干掉。

n = int(input())
def copy(ans,tmp,sx,sy):
    for i in range(sx,sx+len(tmp)):
        ans[i][sy:sy+len(tmp[0])] = tmp[i-sx][:]
def solve(dep):
    if dep == 1:
        return [
            [0,0,1,0,0],
            [0,1,0,1,0],
            [1,0,1,0,1],
        ]
    tmp = solve(dep-1)
    ans = [[0] * (2*len(tmp[0])+1) for i in range(2*len(tmp))]
    copy(ans,tmp,0,1 + (len(tmp[0]) >> 1))
    copy(ans,tmp,len(tmp),0)
    copy(ans,tmp,len(tmp),1 + len(tmp[0]))
    return ans
ans = solve(n)
for i,line in enumerate(ans):
    line.reverse()
    line = line[line.index(1):]
    line.reverse()
    ans[i] = ''.join([' ' if not v else '*' for v in line])
ans.extend([' ' * (len(ans[-1])>>1) + '*'] * n)
for line in ans: print(line)