Tree

ELI5 — The Vibe Check

A tree is a data structure shaped like an upside-down tree — one root at the top, branches going down, and leaves at the very bottom. Each item (node) can have children. The DOM in your browser is a tree. File systems are trees. Family trees are trees. They are great for hierarchical data.

Real Talk

A tree is a hierarchical data structure consisting of nodes connected by edges, with one root node at the top and child nodes branching below. Trees are acyclic (no loops). Important tree types include binary trees (max 2 children), binary search trees (BST, ordered for O(log n) search), AVL/red-black trees (self-balancing), tries (prefix trees), and heaps. The DOM, file systems, and ASTs are all tree structures.

Show Me The Code

// Binary Search Tree node:
class TreeNode {
  constructor(value) {
    this.value = value;
    this.left = null;
    this.right = null;
  }
}

// BST property: left < node < right
//       8
//      / \
//     3   10
//    / \    \
//   1   6    14
// Search is O(log n) in a balanced tree

When You'll Hear This

"The file system is a tree — use recursion to traverse it." / "A BST gives you O(log n) search if it stays balanced."