Binary Search vs Two Pointers: Complete Comparison for Interviews
Choosing between Binary Search and Two Pointers is a common dilemma in coding interviews. Both are powerful algorithmic patterns, but they solve different types of problems. This guide provides a head-to-head comparison with feature matrix, use-case scenarios, and a clear verdict on when to use each.
Feature Comparison Matrix
What is Binary Search?
Divide search space in half for logarithmic time lookups.
Best for: Sorted array search, Boundary finding, Optimization problems
Time Complexity: O(log n)
When to use: Choose Binary Search when the problem involves Sorted array search or Boundary finding.
What is Two Pointers?
Use two pointers converging or diverging on sorted arrays or linked lists.
Best for: Pair sum, Remove duplicates, Container problems
Time Complexity: O(n)
When to use: Choose Two Pointers when the problem involves Pair sum or Remove duplicates.
Key Differences
Use-Case Recommendations
Verdict
Use Binary Search when: Sorted array search, Boundary finding, Optimization problems.
Use Two Pointers when: Pair sum, Remove duplicates, Container problems.
Both combined: In some problems, you can use Binary Search as a sub-routine within Two Pointers or vice versa. Look for these hybrid opportunities in Hard-level problems.
Both patterns are essential for a well-rounded interview preparation. Master each individually before attempting to combine them.
Frequently Asked Questions
Is Binary Search harder than Two Pointers?
Can I use Binary Search and Two Pointers together?
Which should I learn first?
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