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Binary Tree

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Binary Tree

Binary Tree is simple if you keep it on paper. Asha uses it for folder on disk in a file explorer.

Binary Tree on the board — left < root < right. Then say what folder on disk looks like after.

Skip Binary Tree and unbalanced BST becoming a list shows up in a file explorer.

Use Binary Tree when folder on disk must stay clear. If a simpler DSA step works, use that instead.

If folder on disk breaks under Binary Tree, check unbalanced BST becoming a list first.

After Binary Tree, Asha should still remember unbalanced BST becoming a list.

One breath for Binary Tree, then folder on disk, then unbalanced BST becoming a list. Sit down.

Exam tip

For Binary Tree: definition + a file explorer + one failure.

Example

class Node:
    def __init__(self, val, left=None, right=None):
        self.val, self.left, self.right = val, left, right

def inorder(n):
    if not n:
        return []
    return inorder(n.left) + [n.val] + inorder(n.right)

root = Node(2, Node(1), Node(3))
print(inorder(root))

Binary Tree — inorder walks left → node → right (sorted order for a BST).

Short notes

DefBinary Tree — Asha uses it for folder on disk in a file explorer.
RuleBinary Tree → left < root < right.
RememberBinary Tree + Big-O (a file explorer).
UseBinary Tree in a file explorer (folder on disk).
TrapBinary Tree — unbalanced BST becoming a list.
ExBinary Tree → folder on disk.

class Node: def __init__(self, val, left=None, right=None): self.val, self.left, self.right = val, left, right def inorder(n): if not n: return [] return inorder(n.left) + [n.val] + inorder(n.right) root = Node(2, Node(1), Node(3)) print(inorder(root))

Binary Tree

Example

Short notes

Questions

Binary Tree

Example

Short notes

Questions