mirror of
https://github.com/correl/euler.git
synced 2024-11-23 19:19:53 +00:00
30 lines
887 B
Python
30 lines
887 B
Python
|
import math
|
||
|
|
|
||
|
|
def lexicographic_permutation(list, position):
|
||
|
|
items = len(list)
|
||
|
|
list = sorted(list)
|
||
|
|
p = []
|
||
|
|
position = position - 1
|
||
|
|
while len(p) < items:
|
||
|
|
index = 0
|
||
|
|
# Find the next index to pop
|
||
|
|
l = len(list) - 1
|
||
|
|
f = math.factorial(l) if l else 0
|
||
|
|
while position and position >= f:
|
||
|
|
position = position - f
|
||
|
|
index = index + 1
|
||
|
|
|
||
|
|
p.append(list.pop(index))
|
||
|
|
return p
|
||
|
|
|
||
|
|
if __name__ == '__main__':
|
||
|
|
print 'Testing permutations of 0..2:'
|
||
|
|
list = [str(i) for i in [0, 1, 2]]
|
||
|
|
for i in range(1, math.factorial(len(list)) + 1):
|
||
|
|
p = lexicographic_permutation(list, i)
|
||
|
|
print '\tPermutation', i, ''.join(p)
|
||
|
|
|
||
|
|
list = [str(i) for i in [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]]
|
||
|
|
p = lexicographic_permutation(list, 1000000)
|
||
|
|
print '1 millionth lexicographic permutation of 0..9:', ''.join(p)
|