Create 78_Subsets.md

Author: koji

78_Subsets.md

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+## 78. Subsets
+
+
+Given a set of distinct integers, nums, return all possible subsets (the power set).
+
+Note: The solution set must not contain duplicate subsets.
+
+Example:
+
+Input: nums = [1,2,3]
+Output:
+[
+ [3],
+ [1],
+ [2],
+ [1,2,3],
+ [1,3],
+ [2,3],
+ [1,2],
+ []
+]
+
+
+```python
+def subsets(self, nums: List[int]) -> List[List[int]]:
+ 
+ result = []
+ def traverse(build, index):
+ if len(nums) == index:
+ result.append(build)
+ return
+ 
+ traverse(build, index+1)
+ traverse(build+[nums[index]], index+1)
+ 
+ 
+ traverse([], 0)
+ return result
+```
+
+
+```
+Runtime: 32 ms, faster than 77.43% of Python3 online submissions for Subsets.
+Memory Usage: 14.3 MB, less than 100.00% of Python3 online submissions for Subsets.
+```