How do you return all permutations of a string in python?
View Discussion Show Improve Article Save Article View Discussion Improve Article Save Article Given a string, write a Python program to find out all possible permutations of a string. Let’s discuss a few methods to solve the
problem. Python3
Output: Initial string abc Resultant permutations ['abc', 'acb', 'bac', 'bca', 'cba', 'cab'] Python3
Output: Initial string abc Resultant List ['abc', 'acb', 'bac', 'bca', 'cab', 'cba'] View Discussion Improve Article Save Article View Discussion Improve Article Save Article A permutation also called an “arrangement number” or “order,” is a rearrangement of the elements of an ordered list S into a one-to-one correspondence with S itself. A string of length n has n! permutation. Source: Mathword(http://mathworld.wolfram.com/Permutation.html) Below are the permutations of string ABC. Here is a solution that is used as a basis in backtracking. Python3
Output: ABC ACB BAC BCA CBA CAB Algorithm Paradigm: Backtracking Time Complexity: O(n*n!) Note that there are n! permutations and it requires O(n) time to print a permutation. Auxiliary Space: O(r – l) Note: The above solution prints duplicate permutations if there are repeating characters in the input string. Please see the below link for a solution that prints only distinct permutations even if there are duplicates in input. Another approach: Python3
Output: Enter the string : abc All possible strings are : abc acb bac bca cab cba Time Complexity: O(n*n!) The time complexity is the same as the above approach, i.e. there are n! permutations and it requires O(n) time to print a permutation. Auxiliary Space: O(|s|) How do I return a permutation of a string?Using a backtracking approach, all the permutations of the given string can be printed.. Swap S[i] and S[idx].. Construct all other possible permutations, from backtrack(idx + 1).. Backtrack again, i.e. swap(S[i], S[idx]).. How do you generate every permutation of a string?Step 1: Merge [a] and b: [ba, ab] Step 2: Merge [ba, ab] and c: [cba, bca, bac, cab, acb, abc] Step 3: Merge [cba, bca, bac, cab, acb, abc] and d: [dcba, cdba, cbda, cbad, dbca, bdca, bcda, bcad, dbac, bdac, badc, bacd, dcab, cdab, cadb, cabd, dacb, adcb, acdb, acbd, dabc, adbc, abdc, abcd]
How do you find all permutations?To calculate the number of permutations, take the number of possibilities for each event and then multiply that number by itself X times, where X equals the number of events in the sequence. For example, with four-digit PINs, each digit can range from 0 to 9, giving us 10 possibilities for each digit.
How do you find the number of permutations in Python?To calculate permutations in Python, use the itertools. permutation() method. The itertools. permutations() method takes a list, dictionary, tuple, or other iterators as a parameter and returns the permutations of that list.
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