Permutations by swapping: Difference between revisions

===Python: recursivesimpler===

After spotting the pattern of highest number being inserted into each perm of lower numbers from right to left, then left to right, I developed this recursivesimpler iterative function:

def s_perm(items): = [[]]

for j in if items <= 0range(n):

new_items = return [[]]

elsefor i, item in enumerate(items):

new_itemsif =i []% 2:

for i, item in enumerate(s_perm(items# -step 1)):down

ifnew_items += [item[:i] %+ 2[j] + item[i:] \

# step down for i in range(len(item), -1, -1)]

# step for i in range(len(item), -1, -1)]up

elsenew_items += [item[:i] + [j] + item[i:] \

# step up for i in range(len(item) + 1)]

items = new_items += [item[:i] + [items - 1] + item[i:] \

for i, item in enumerate(s_perm(n)items)]</lang>