elian ambigram finder

# if this is somehow copyrightable then cc0 (do whatever): https://creativecommons.org/publicdomain/zero/1.0/

import math
import string

alphabet = string.ascii_lowercase + "&"
upside_down = {}
for i in range(len(alphabet)):
    upside_down[alphabet[i]] = alphabet[math.floor(i/9)*9 + 8-(i%9)] # 012345678 -> 876543210

def flip(s):
    return "".join([upside_down[i] if i in upside_down else i for i in s])[::-1]

with open("words.txt", "r") as f:
    words = {word.lower() : 0 for word in f.read().splitlines()} # dict is hashmap so fast lookup

found = {} # dict keeps order so we can preserve the alphabetizedness
for i in words:
    if flip(i) in words:
        found[tuple(sorted((i, flip(i))))] = None
found = sorted(found, key = lambda i: len(i[0]), reverse = True)

print(len(found))

with open("elian ambigrams.txt", "w") as f:
    f.write("\n".join([" ".join(i) for i in found]))