Subsets

MediumBacktracking

Asked byFacebookAmazonGoogleBloombergMicrosoftApple

Problem

Given an array of unique integers, return all possible subsets (the power set), without duplicate subsets.

Examples

Example 1

Input:nums = [1,2,3]

Output:[[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]

Constraints

1 <= nums.length <= 10

Solve it in the editor. Sign in free to run your Python or JavaScript against test cases, get a verdict, and track your attempts.

Solve on FeatCode →

How to approach it: the Backtracking pattern

Explore a decision one choice at a time, undo it if it doesn't lead anywhere, and try the next option. It's a systematic way to generate every valid combination, permutation, or arrangement.

Look for this pattern when

The problem asks for "all possible" combinations, subsets, permutations, or valid arrangements.
A greedy or direct-formula approach doesn't work because you genuinely need to explore multiple branches.

Read the full Backtracking guide →

Video walkthroughs

Original problem on LeetCode ↗