Yosgi Siqi Liu

Deleting a node from a binary search tree by locating it via the BST property, then handling the three deletion cases.

Trimming a BST to a value range by recursing into the correct branch using the BST bounds.

Constructing a binary search tree from its pre-order sequence by recursively inserting each value.

Connecting each node to its right neighbor per level, reusing the previous layer's links to reach constant space.

Generating all possible full binary trees with recursion that combines left and right subtree counts (DP).

Serializing a binary tree with BFS and deserializing it using parent/child index relationships.

Finding the longest zigzag path in a binary tree with DFS that tracks direction and length, handling the boundary cases.

Techniques and examples for breadth-first (level-order) traversal of binary trees.

Collecting all root-to-leaf paths with a given sum using DFS with backtracking.

Notes on binary tree traversal — why DFS uses a stack and BFS a queue, with reusable pre/in/post-order and level-order templates.