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62 lines
2.3 KiB
Python
62 lines
2.3 KiB
Python
#Python/pyClasses/StringAlgorithms.py
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#Matthew Ellison
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# Created: 07-21-21
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#Modified: 07-21-21
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#This file contains my library of string functions
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"""
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Copyright (C) 2021 Matthew Ellison
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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"""
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#This is a function that creates all permutations of a string and returns a vector of those permutations.
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def getPermutations(master: str, num: int = 0) -> list:
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perms = []
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#Check if the number is out of bounds
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if((num >= len(master)) or (num < 0)):
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#Do nothing and return and empty list
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perms
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#If this is the last possible recurse just return the current string
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elif(num == (len(master) - 1)):
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perms.append(master)
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#If there are more possible recurses, recurse with the current permutations
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else:
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temp = getPermutations(master, num + 1)
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perms += temp
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#You need to swap the current letter with every possible letter after it
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#The ones needed to swap before will happen automatically when the function recurses
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for cnt in range(1, len(master) - num):
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#Swap two elements
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master = master[0:num] + master[num + cnt] + master[num + 1 : num + cnt] + master[num] + master[num + cnt + 1:]
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#Get the permutations after swapping two elements
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temp = getPermutations(master, num + 1)
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perms += temp
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#Swap the elements back
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master = master[0:num] + master[num + cnt] + master[num + 1 : num + cnt] + master[num] + master[num + cnt + 1:]
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#The array is not necessarily in alpha-numeric order. So if this is the full array sort it before returning
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if(num == 0):
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perms.sort()
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#Return the list
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return perms
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#Returns true if the string passed in is a palindrome
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def isPalindrome(str: str) -> bool:
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rev = str[::-1]
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if(str == rev):
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return True
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else:
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return False
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