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Complete Binary Tree

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Complete Binary Tree

Complete Binary Tree is a DSA idea you prove with folder on disk, not with a slogan.

Do Complete Binary Tree once by hand. left < root < right. Change one input. Say the new result out loud.

Without Complete Binary Tree, a file explorer gets messy and folder on disk is hard to trust.

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

Complete Binary Tree trap — unbalanced BST becoming a list. Neha loses marks for that every viva.

Place Complete Binary Tree next to nearby DSA work — left < root < right is the link.

Viva for Complete Binary Tree — what it is → left < root < right → the mistake (unbalanced BST becoming a list).

Exam tip

For Complete 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))

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

Short notes

DefComplete Binary Tree — Neha uses it for folder on disk in a file explorer.
RuleComplete Binary Tree → left < root < right.
RememberComplete Binary Tree + Big-O (a file explorer).
UseComplete Binary Tree in a file explorer (folder on disk).
TrapComplete Binary Tree — unbalanced BST becoming a list.
ExComplete Binary 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))

Complete Binary Tree

Example

Short notes

Questions

Complete Binary Tree

Example

Short notes

Questions