Done Backtracking-1

[vaishnavi2231]

No description provided.

[super30admin]

Your solutions for Combination Sum are excellent. You have implemented multiple approaches, which shows a strong grasp of backtracking and recursion. Here are some points to consider:

1. For Solution 1 and Solution 3, you correctly use backtracking by appending and then popping. This is efficient in terms of space because it avoids creating multiple copies of the path.

2. In Solution 2, you use deepcopy to create new lists. While this is correct, it is less efficient in terms of both time and space. However, it is a valid approach and easier to reason about for some.

3. You have correctly analyzed the time and space complexities for each solution. However, for the time complexity of Solution 1 and Solution 3, a more precise expression might be O(2^(target/min_candidate)), but your notation is acceptable.

4. The code is clean and well-commented. It's great that you have included comments about the logic and base cases.

5. One suggestion: In Solution 1, the base case checks if i >= len(candidates) or target < 0. Actually, the condition target < 0 can be checked at the beginning of the function to avoid unnecessary recursion. However, your current implementation is correct.

6. For Solution 3, the for-loop based recursion is a common pattern for combination problems. It is efficient and avoids duplicate combinations by using the pivot.

Overall, your solutions are correct, efficient, and well-written. Keep up the good work!