46-Permutations.py

'''Leetcode- https://leetcode.com/problems/permutations/'''
'''
Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.

Example 1:

Input: nums = [1,2,3]
Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
'''


defpermute(nums):
result= []

# base case
iflen(nums) ==1:
return [nums.copy()] #ornums[:] is a deep copy

foriinrange(len(nums)):
n=nums.pop()
perms=permute(nums)

forperminperms:
perm.append(n)
result.extend(perms)
nums.append(n)
returnresult

#T:O(2^n)
#S:O(n)