Two Pointer Technique: When to Use It and 6 Problems Solved
A pattern-recognition guide to the two pointer technique for coding interviews. Explains the three flavors (converging pointers on sorted data, fast/slow same-direction pointers, and pointers across two sequences) and the problem-statement signals that tell you which one to reach for. Works through six interview problems from easy to hard with Python solutions: Two Sum II, Valid Palindrome, Remove Duplicates from Sorted Array, Container With Most Water, 3Sum, and Trapping Rain Water. Covers why the converging-pointer proof works, the deduplication details that break 3Sum, and a checklist for spotting two pointer problems in the wild.