Title: Permutations Source: leetcode.com
Given a collection of numbers, return all possible permutations.
For example,
[1,2,3] have the following permutations:
[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].
Python solution
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''' https://leetcode.com/problems/permutations/ ''' class Solution(object): def __init__(self): self.lst = [] def helper(self, curr, rem): if not rem: self.lst.append(curr) else: ln = len(rem) for i in range(0, ln): self.helper(curr + [rem[i]], rem[:i] + rem[i+1:]) def permute(self, nums): """ :type nums: List[int] :rtype: List[List[int]] """ if not nums: return self.lst self.helper([], nums) return self.lst |