[LeetCode][릿코드][Python][#46] Permutations

https://leetcode.com/problems/permutations/

Permutations - LeetCode

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]]

Example 2:

Input: nums = [0,1]
Output: [[0,1],[1,0]]

Example 3:

Input: nums = [1]
Output: [[1]]

 

Constraints:

• 1 <= nums.length <= 6
• -10 <= nums[i] <= 10
• All the integers of nums are unique.

---

깊이 우선 탐색 (DFS: Depth-First Search) 방법을 사용하여 문제를 풀 수 있다.

아래와 같이 탐색하는 알고리즘을 구현한다.

 

class Solution:
    def permute(self, nums):
        result , visited = [], []
        def dfs(nums):
            if len(nums) == 0:
                result.append(visited[:])
            for num in nums:
                next = nums[:]
                next.remove(num)
                visited.append(num)
                dfs(next)
                visited.pop()

        dfs(nums)
        return result