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zpconn/inverse_phone.py

Created January 15, 2014 22:08
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A solution to the inverse telephone problem in Python (with no imports). Given a mapping like 1 -> A,B,C 2 -> D,E,F etc. and a string of integers like "112", determine all possible images of this string under the mapping ("AAD", "AAE", etc.).
Raw
inverse_phone.py
def product(lists):
result = [[]]
for l in lists:
result = [x + [y] for x in result for y in l]
for prod in result:
yield prod
def inverse_phone(mappings, s):
numbers = set([int(n) for n in s])
combinations = product([mappings[n] for n in numbers])
output = []
for combination in combinations:
possibility = ""
for c in s:
possibility += combination[int(c) - 1]
output.append(possibility)
return output
mappings = {1: ['a', 'b', 'c'], 2: ['d', 'e', 'f'], 3: ['g', 'h', 'i', 'j']}
print inverse_phone(mappings, "132")
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