**Strings in Python:**

Strings are simple text in programming, which might be individual letters, words, phrases, or whole sentences. Python strings have powerful text-processing capabilities, such as searching and replacing characters, cutting characters, and changing case. Empty strings are written as two quotations separated by a space. Single or double quotation marks may be used. Three quote characters can be used to easily build multi-line strings.

Given a string ,the task is to print all the permutations of the given string in lexicographic order without using recursion in Python.

**Examples:**

**Example1:**

**Input:**

given string ='hug'

**Output:**

printing all [ hug ] permutations : hug ugh uhg ghu guh hgu

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**Example2:**

**Input:**

given string ='tork'

**Output:**

printing all [ tork ] permutations : tork trko trok kort kotr krot krto ktor ktro okrt oktr orkt ortk otkr otrk rkot rkto rokt rotk rtko rtok tkor tkro tokr

## Program to Print All Permutations of a String in Lexicographic Order without Recursion

Below are the ways to Print All string permutations without recursion in lexicographic order:

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### 1)Using for and while Loops(Static Input)

**Approach:**

- Give the string as static input.
- The algorithm works by first generating a loop that will run n! times, where n is the length of the string.
- Each loop iteration produces the string and looks for its next variant to print in the following iteration.
- The following is the next higher permutation.
- If we call our sequence seq, we identify the least index p such that all entries in seq[p…end] are in decreasing order.
- If seq[p…end] represents the whole sequence, i.e. p == 0, then seq is the highest permutation. So we simply reverse the entire string to find the shortest permutation, which we regard to be the next permutation.
- If p > 0, we reverse seq[p…end].

**Below is the implementation:**

from math import factorial def printPermutationsLexico(string): # In lexicographic sequence, print all permutations of string s. stringseq = list(string) # There will be n! permutations where n = len (seq). for t in range(factorial(len(stringseq))): # print permutation by joining all the characters using join() function print(''.join(stringseq)) # Find p such that seq[per:] is the longest sequence with lexicographic # elements in decreasing order. per = len(stringseq) - 1 while per > 0 and stringseq[per - 1] > stringseq[per]: per -= 1 # reverse the stringsequence from per to end using reversed function stringseq[per:] = reversed(stringseq[per:]) if per > 0: # Find q such that seq[q] is the smallest element in seq[per:] and seq[q] is greater # than seq[p - 1].Find q such that seq[q] is the smallest # element in seq[per:] and seq[q] is greater than seq[per - 1]. q = per while stringseq[per - 1] > stringseq[q]: q += 1 # swapping seq[per - 1] and seq[q] stringseq[per - 1], stringseq[q] = stringseq[q], stringseq[per - 1] # given string as static input given_string = 'hug' # printing all the perumutations print('printing all [', given_string, '] permutations :') # passing given string to printPermutationsLexico function printPermutationsLexico(given_string)

**Output:**

printing all [ hug ] permutations : hug ugh uhg ghu guh hgu

**Explanation:**

- User must give string input as static .
- On the string, the method printPermutationsLexico is called.
- The function then prints the string’s permutations in lexicographic order.

### 2)Using for and while Loops(User Input)

**Approach:**

- Enter some random string as user input using int(input()) function.
- The algorithm works by first generating a loop that will run n! times, where n is the length of the string.
- Each loop iteration produces the string and looks for its next variant to print in the following iteration.
- The following is the next higher permutation.
- If we call our sequence seq, we identify the least index p such that all entries in seq[p…end] are in decreasing order.
- If seq[p…end] represents the whole sequence, i.e. p == 0, then seq is the highest permutation. So we simply reverse the entire string to find the shortest permutation, which we regard to be the next permutation.
- If p > 0, we reverse seq[p…end].

**Below is the implementation:**

from math import factorial def printPermutationsLexico(string): # In lexicographic sequence, print all permutations of string s. stringseq = list(string) # There will be n! permutations where n = len (seq). for t in range(factorial(len(stringseq))): # print permutation by joining all the characters using join() function print(''.join(stringseq)) # Find p such that seq[per:] is the longest sequence with lexicographic # elements in decreasing order. per = len(stringseq) - 1 while per > 0 and stringseq[per - 1] > stringseq[per]: per -= 1 # reverse the stringsequence from per to end using reversed function stringseq[per:] = reversed(stringseq[per:]) if per > 0: # Find q such that seq[q] is the smallest element in seq[per:] and seq[q] is greater # than seq[p - 1].Find q such that seq[q] is the smallest # element in seq[per:] and seq[q] is greater than seq[per - 1]. q = per while stringseq[per - 1] > stringseq[q]: q += 1 # swapping seq[per - 1] and seq[q] stringseq[per - 1], stringseq[q] = stringseq[q], stringseq[per - 1] # Enter some random string as user input using int(input()) function. given_string =input('Enter some random string = ') # printing all the perumutations print('printing all [', given_string, '] permutations :') # passing given string to printPermutationsLexico function printPermutationsLexico(given_string)

**Output:**

Enter some random string = epic printing all [ epic ] permutations : epic icep icpe iecp iepc ipce ipec pcei pcie peci peic pice piec ceip cepi ciep cipe cpei cpie ecip ecpi eicp eipc epci

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