6 articles
Master reversing a subrange of a linked list in-place in a single pass. A classic interview problem at Facebook, Microsoft, and Amazon that tests your pointer manipulation skills and ability to handle complex multi-pointer state.
Learn three ways to flatten a binary tree to a pre-order linked list in-place, including the O(1) space Morris-style approach. A classic interview problem at Microsoft, Amazon, and Google that bridges tree and linked list manipulation.
LC 328 Odd Even Linked List is a medium interview problem at Facebook, Amazon, and LinkedIn that tests your ability to maintain two separate pointer chains simultaneously. Learn the O(1) space two-chain pattern with Python and JavaScript, a visual dry run, and interview tips.
String Compression (LC 443) is a deceptively careful two-pointer problem with strict in-place memory requirements. Master the read-write pointer pattern and you have the blueprint for in-place array transformations across many FAANG questions.
LC 114 Flatten Binary Tree to Linked List rearranges a binary tree into a right-skewed linked list in pre-order. The optimal O(1) space solution uses a Morris-like pointer manipulation trick tested at Amazon and Microsoft.
Sort an array of 0s, 1s, and 2s in one pass with no extra space using the Dutch National Flag algorithm. Three pointers maintain sorted invariants for all three partitions simultaneously.