Completed Backtracking-1

[prattiiksha]

No description provided.

[super30admin]

Combination Sum (combination_sum_282.cpp)

Strengths:

• Correctly implements backtracking with proper push/pop pattern
• Uses index-based recursion to avoid duplicate combinations
• More space-efficient than the reference solution by avoiding deep copies
• Clean separation between public interface and recursive helper

Areas for Improvement:

• The comment "logic" before the for loop is misleading - consider renaming to "backtrack" or "explore choices"
• The class has inconsistent indentation which affects readability
• Consider adding a check for i == candidates.size() as a base case for completeness
• The empty check candidates.size()==0 is unnecessary given constraints (minimum size is 1)

VERDICT: PASS

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Operations and expressions (expressionAdd_operator_39.cpp)

Strengths:

• Good understanding of the backtracking approach for this classic problem
• Correctly handles the three operators and their precedence
• Clean variable naming and logical structure
• Proper use of long to handle large numbers

Areas for Improvement:

1. Fix the leading zero bug: Change num[index] to num[i] in the condition
2. Add early return statement after the empty check
3. Consider using StringBuilder instead of string concatenation for better performance (as shown in the reference solution)
4. Add comments explaining the key logic, especially the multiplication precedence handling
5. Mark parameters as final where appropriate for better code clarity

The solution is functionally correct and demonstrates good problem-solving skills. The identified bug with the leading zero check is a subtle but important fix that ensures proper validation of operands.

VERDICT: NEEDS_IMPROVEMENT