Given a list of elements in lexicographical order (i.e. [‘a’, ‘b’, ‘c’, ‘d’]), find the nth permutation – Average time to solve?

9 min, including test

import math

def nthperm(li, n):
    n -= 1
    s = len(li)
    res = []
    if math.factorial(s) <= n:
        return None
    for x in range(s-1,-1,-1):
        f = math.factorial(x)
        d = n / f
        n -= d * f
        res.append(li[d])
        del(li[d])
    return res

#now that's fast...
nthperm(range(40), 123456789012345678901234567890)

Related Contents:

  1. Basics of recursion in Python
  2. How to do a recursive sub-folder search and return files in a list?
  3. Python recursion with list returns None [duplicate]
  4. Making all possible combinations of a list
  5. Flattening a list recursively [duplicate]
  6. How to find common elements in list of lists?
  7. Confusing […] List in Python: What is it?
  8. Accessing the index in ‘for’ loops
  9. How do I convert two lists into a dictionary?
  10. How to group dataframe rows into list in pandas groupby
  11. Why does “return list.sort()” return None, not the list?
  12. How does assignment work with list slices?
  13. How to define a two-dimensional array?
  14. Identify groups of continuous numbers in a list
  15. How to check if a string is a substring of items in a list of strings?
  16. What is the difference between `sorted(list)` vs `list.sort()`?
  17. Copying nested lists in Python
  18. Removing elements that have consecutive duplicates
  19. How slow is Python’s string concatenation vs. str.join?
  20. Merge lists that share common elements
  21. Pandas DataFrame to List of Dictionaries
  22. In Python, what is the difference between “.append()” and “+= []”?
  23. Creating a list of dictionaries results in a list of copies of the same dictionary
  24. Python – TypeError: ‘int’ object is not iterable
  25. Alphabet range in Python
  26. Find nearest indices for one array against all values in another array – Python / NumPy
  27. How do I multiply each element in a list by a number?
  28. Finding first and last index of some value in a list in Python
  29. What is the inverse function of zip in python? [duplicate]
  30. How to find the min/max value of a common key in a list of dicts?
  31. Modifying a list inside a function
  32. Explicitly select items from a list or tuple
  33. Filtering a list based on a list of booleans
  34. How to remove multiple items from a list in just one statement?
  35. How to access the elements of a 2D array?
  36. Matplotlib Graph Data
  37. How to get the n next values of a generator into a list
  38. How to append multiple values to a list in Python
  39. appending list but error ‘NoneType’ object has no attribute ‘append’ [duplicate]
  40. What is the ‘pythonic’ equivalent to the ‘fold’ function from functional programming?
  41. Why does a for-loop with pop-method (or del statement) not iterate over all list elements [duplicate]
  42. Deleting node in BST Python
  43. What is time complexity of a list to set conversion?
  44. Big-O of list slicing
  45. Replacing a sublist with another sublist in python
  46. How to override the slice functionality of list in its derived class
  47. Difference between using [] and list() in Python
  48. How to flatten a hetrogenous list of list into a single list in python? [duplicate]
  49. Using a dict to translate numbers to letters in python
  50. How to convert a set to a list in python?

Leave a Comment