# Leetcode 78. Subsets

## 題解

### DFS Back Tracking

class Solution:
    def subsets(self, nums: List[int]) -> List[List[int]]:
        n = len(nums)
        output = []
        def dfs(start: int, ans: List[int]):
            output.append(ans[:])
            for i in range(start,n):
                ans.append(nums[i])
                dfs(i+1,ans)
                ans.pop()
        dfs(0,[])
    return output