Add implementation for leetcode problems 78, 131

[rishigoswamy]

No description provided.

[super30admin]

Subsets (leetcode_131.py)

Your solution for palindrome partitioning is well-structured and uses a standard backtracking approach. However, there are a few points to note:

1. You are solving the wrong problem. The problem assigned was "Subsets", which requires generating all subsets of a given array of integers. Your code is for "Palindrome Partitioning", which partitions a string into palindromic substrings. Please double-check the problem statement next time.
2. For the palindrome partitioning problem, using copy.deepcopy is inefficient. Instead, you can use path[:] or list(path) to create a shallow copy of the path when adding to results, as the path contains strings which are immutable.
3. The function name and parameters should match the problem requirements. For "Subsets", the function should be named subsets and take a list of integers as input.

For the "Subsets" problem, you can use a similar backtracking approach but with a different base case and recursive structure. Here's a hint: you can generate subsets by either including or excluding each element at every step.

VERDICT: NEEDS_IMPROVEMENT

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Palindrome Partitioning (leetcode_78.py)

Strengths:

• Your code for the "Subsets" problem is well-written and follows a standard backtracking approach.
• The comments are clear and explain the logic well.
• You have correctly analyzed the time and space complexity for the "Subsets" problem.

Areas for Improvement:

• It seems there was a misunderstanding: the problem you solved is "Subsets" (LeetCode 78), but the problem you were asked to solve is "Palindrome Partitioning" (LeetCode 131). Please double-check the problem statement before starting.
• For "Palindrome Partitioning", you need to generate all partitions of the string such that each substring is a palindrome. This requires checking each substring for being a palindrome during the backtracking process.
• You should implement a similar backtracking approach but with a palindrome check for each substring. The reference solution provided in C++ can be a good guide.

Suggestions for "Palindrome Partitioning":

1. Use a helper function that takes the string, a starting index (pivot), and a current path.
2. When the pivot reaches the end of the string, add the path to the result.
3. For each index from pivot to the end, extract the substring from pivot to i.
4. Check if that substring is a palindrome. If yes, add it to the path, recurse with i+1 as the new pivot, and then backtrack by popping the substring.
5. Implement a helper function to check if a string is a palindrome (using two pointers).

Example of palindrome check function in Python:

def is_palindrome(s):
    left, right = 0, len(s)-1
    while left < right:
        if s[left] != s[right]:
            return False
        left += 1
        right -= 1
    return True

VERDICT: NEEDS_IMPROVEMENT