Subsets
Given an integer array nums of unique elements, return all possible subsets (the power set). The solution set must not contain duplicate subsets. It is guaranteed that 0 <= nums.length <= 10.
Constraints:
- 1 <= nums.length <= 10
- All elements in nums are unique
Examples:
Input: [1, 2, 3]
Output: [[], [1], [2], [1, 2], [3], [1, 3], [2, 3], [1, 2, 3]]
Explanation: The subsets of [1, 2, 3] are all possible subsets, including the empty subset and the subset containing all elements.
Solutions
Backtracking
Time: O(2^n)Space: O(2^n)
The backtracking approach generates all possible subsets by adding each element to the current subset and then recursively generating all subsets of the remaining elements.
def subsets(nums):
res = [];
def backtrack(start, path):
res.append(path); for i in range(start, len(nums)):
path.append(nums[i]); backtrack(i + 1, path); path.pop(); backtrack(0, []); return resFollow-up:
Generate all possible subsets of a given array of integers, where each integer can be used more than once.
