mirror of
https://github.com/jlengrand/project_euler.git
synced 2026-03-10 08:41:20 +00:00
5d55ff3f50
Work on primes to be performed. dump has been created to avoid recalculation each time. But I 'll spend some time working on sieves. Signed-off-by: Julien Lengrand-Lambert <julien@lengrand.fr>
38 lines
1.2 KiB
Python
38 lines
1.2 KiB
Python
#!/usr/bin/env python
|
|
"""
|
|
##---
|
|
# Julien Lengrand-Lambert
|
|
#Created on : Thu Jan 19 10:12:06 CET 2012
|
|
#
|
|
# DESCRIPTION : Solves problem 24 of Project Euler
|
|
A permutation is an ordered arrangement of objects. For example, 3124 is one
|
|
possible permutation of the digits 1, 2, 3 and 4. If all of the permutations are
|
|
listed numerically or alphabetically, we call it lexicographic order.
|
|
The lexicographic permutations of 0, 1 and 2 are:
|
|
012 021 102 120 201 210
|
|
|
|
What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9?
|
|
##---
|
|
"""
|
|
def lexi_perm(str, num):
|
|
"""
|
|
Returns the numst lexicographic permutations of all values in str
|
|
"""
|
|
# already sorted by all_permutations!
|
|
return int(all_permutations(str)[num - 1])
|
|
|
|
def all_permutations(seq):
|
|
"""permutate a sequence and return a list of the permutations"""
|
|
if not seq:
|
|
return [seq] # is an empty sequence
|
|
else:
|
|
temp = []
|
|
for k in range(len(seq)):
|
|
part = seq[:k] + seq[k+1:]
|
|
for m in all_permutations(part):
|
|
temp.append(seq[k:k+1] + m)
|
|
return temp
|
|
|
|
if __name__ == '__main__' :
|
|
print "Answer is : %d" %(lexi_perm("0123456789", 1000000))
|