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32 lines
852 B
Python
32 lines
852 B
Python
#!/bin/python
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"""
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Write a recursive function for generating all permutations of an input string. Return them as a set.
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"""
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def get_permutations(string):
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if len(string) < 2:
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return set([string])
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all_chars_except_last = string[:-1]
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last_char = string[-1]
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permutations_of_all_chars_except_last = get_permutations(all_chars_except_last)
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permutations = set()
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for permutation_of_all_chars_except_last in permutations_of_all_chars_except_last:
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for position in range(len(all_chars_except_last) + 1):
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permutation = (
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permutation_of_all_chars_except_last[:position]
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+ last_char
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+ permutation_of_all_chars_except_last[position:]
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)
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permutations.add(permutation)
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return permutations
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str = "abcd"
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print get_permutations(str) |