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# permutations: no repeat characters
def char_and_rest(i, xs):
return xs[i], xs[0:i] + xs[i + 1:]
def permutations(xs):
if len(xs) == 1:
return [xs]
result = []
for c, rest in [char_and_rest(i, xs) for i in range(len(xs))]:
result += [c + perm for perm in permutations(rest)]
return result
expected = ["cat", "cta", "act", "atc", "tca", "tac"]
result = permutations("cat")
print(result, expected)
assert len(result) == len(expected)
assert result == expected
print("Success!")
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