✅ [Python/C++/Java/Rust] 0 ms, bit & set operations (with detailed comments)
\u2705 IF YOU LIKE THIS SOLUTION, PLEASE UPVOTE.\n*\nThis solution employs bit & set operations. Time complexity is exponential: *O(expN). Space complexity is e
**\u2705 IF YOU LIKE THIS SOLUTION, PLEASE UPVOTE.**\n****\nThis solution employs bit & set operations. Time complexity is exponential: **O(expN)**. Space complexity is exponential: **O(expN)**. \n\n| **Language** | [**Python**](https://leetcode.com/submissions/detail/828975733/) | [**C++**](https://leetcode.com/submissions/detail/828974283/) | [**Java**](https://leetcode.com/submissions/detail/829255644/) | [**Rust**](https://leetcode.com/submissions/detail/828985984/) | \n|---|---|---|---|---|\n| **Runtime** | **78 ms (98.70%)** | **0 ms (100.00%)** | **10 ms (90.18%)** | **0 ms (100.00%)** |\n| **Memory** | **51.9 MB  (11.15%)** | **9.7 MB (74.27%)** | **42.1 MB  (88.06%)** | **2.2 MB  (33.33%)** |\n\n<iframe src="https://leetcode.com/playground/75txHQDx/shared" frameBorder="0" width="800" height="660"></iframe>
['C', 'Python', 'Java', 'Rust']