Two Pointers Pattern
Two pointers move through a sequence together — from both ends, or at different speeds — to converge on an answer without nested loops. It shines on sorted data and in-place array manipulation.
Typical complexity: O(n) time (after any sort), O(1) space
When to use it
- The input is sorted (or can be sorted cheaply).
- You're looking for a pair/triple meeting a target.
- You need an in-place partition, dedupe, or reversal.
Practice problems
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