Topics / Two Pointers
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Two Pointers
Two indices walking an array — the technique behind 3Sum, palindrome checks, and container problems.
Why learn Two Pointers?
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Converts many O(n²) brute forces into O(n) one-pass solutions.
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A single pattern that unlocks 30+ classic problems.
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Appears constantly in mid-level interviews.
What you can build with Two Pointers
Sorted-array pair / triple problems Palindrome and substring checks In-place array modification (remove duplicates, move zeros)
Two Pointers tutorials
4 articles · page 1 of 1Hand-written tutorials, ordered as a recommended learning path.
- 01 Sliding Window Master the sliding window technique with fixed and variable window patterns, two pointer variants, and reusable templates for solving LeetCode problems.
- 02 Move Zeroes Solve Move Zeroes in O(n) time and O(1) space using a write pointer. Includes walkthrough, edge cases, and interview tips.
- 03 Remove Duplicates Solve Remove Duplicates from Sorted Array in O(n) time and O(1) space with the two-pointer write-pointer pattern. Includes walkthrough, edge cases, and complexity.
- 04 Two Pointers Master every two pointer pattern for LeetCode: opposite-end, same-direction, and fast/slow pointers with templates, complexity analysis, and 15+ mapped problems.