Basic17.py

# Write a Python program to get all strobogrammatic numbers that are of length n.
#https://github.com/keon/algorithms/blob/master/math/generate_strobogrammtic.py
def gen_strobogrammatic(n):
    '''
    :type n: int
    :rtype: List[str]
    '''
    result = helper(n,n)
    return result

def helper(n,length):
    if n==0:
        return [""]
    if n == 1:
        return ["1","0","8"]
    middles = helper(n-2,length)
    result= []
    for middle in middles:
        if n!= length:
            result.append("0"+middle+"0")
        result.append("8"+middle+"8")
        result.append("1"+middle+"1")
        result.append("9"+middle+"6")
        result.append("6"+middle+"9")
    return result
print("n = 2 : \n",gen_strobogrammatic(2))
print("n = 3",gen_strobogrammatic(3))
print("n = 4 \n",gen_strobogrammatic(4))