9 posts · page 1 of 1
Master every two pointer pattern for LeetCode: opposite-end, same-direction, and fast/slow pointers with templates, complexity analysis, and 15+ mapped problems.
Master the sliding window technique with fixed and variable window patterns, two pointer variants, and reusable templates for solving LeetCode problems.
Solve Move Zeroes in O(n) time and O(1) space using a write pointer. Includes walkthrough, edge cases, and interview tips.
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.
Solve the Reverse String problem in place using the two-pointer technique. Walkthrough, complexity analysis, edge cases, and clean Java, Python, and C++ implementations.
A careful walkthrough of 3Sum using sort plus two pointers. We handle duplicate triplets cleanly and avoid the classic off-by-one traps.
Solve Container With Most Water with the two-pointer technique. We prove correctness and contrast it with the quadratic brute force.
Solve Trapping Rain Water in linear time and constant space using the two-pointer technique. Brute force, optimal walkthrough, and interview talk track.
A practical guide to the two pointers technique — opposite-end and same-direction patterns, when to use each, and six classic interview problems with worked solutions.