Binary Trees

Variants

• → In-order Traversal

  Left → Root → Right. Visits nodes in ascending order on a BST.

• → Pre-order Traversal

  Root → Left → Right. Clones a tree or serialises expression trees.

• → Post-order Traversal

  Left → Right → Root. Bubble information up from children — the basis of every post-order pattern.

• → Path Sum (root → leaf)post-order pattern

  DFS the tree with a running sum; light up any root-to-leaf path that hits the target.

• → Lowest Common Ancestorpost-order pattern

  Recursive descent — both subtrees returning truthy at a node means that node is the LCA.

Variants

• → Maximum Depth (BFS)

  Level-order traversal counting completed levels — every fully drained queue level bumps the depth counter.