[LeetCode] Subsets

문제

Given an integer array nums of unique elements, return all possible subsets (the power set).

The solution set must not contain duplicate subsets. Return the solution in any order.

예제

Example 1:

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

Example 2:

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

조건

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

답

풀이 1

BFS를 활용한 풀이

class Solution:
    def subsets(self, nums: List[int]) -> List[List[int]]:
        ans = []
        sub = []
        
        q = collections.deque()
        q.append([sub, -1])
        
        while q:
            li, index = q.popleft()
            ans.append(li)
            
            if index == len(nums) - 1:
                continue
            for i in range(index+1, len(nums)):
                q.append([li+[nums[i]], i])
        
        return ans

풀이 2

DFS를 활용한 풀이

class Solution:
    def subsets(self, nums: List[int]) -> List[List[int]]:
        result = []
        
        def dfs(index, path):
            # 매번 결과 추가
            result.append(path)
            
            # 경로를 만들면서 DFS
            for i in range(index, len(nums)):
                dfs(i + 1, path + [nums[i]])
        
        dfs(0, [])
        return result