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Two Pointers1 article

Two Pointers

Two pointers shrink the search space from both ends. Once you see sorted input or a pair-sum constraint, reach for this pattern.

Related:Sliding Window

Sliding window or two pointers? Ask the invariant.

Most posts explain what each one is. This one explains the one question that tells you which to use — and why senior engineers still get it wrong under pressure.

Coco · Apr 11, 2026

Practice Two Pointers problems

Container With Most WaterMFind the Duplicate NumberMLongest Palindromic SubstringMMeeting Rooms IIM
All Two Pointers problems