DSA · Theory

Postorder Traversal

Theory

145/810

Postorder Traversal

If you can teach Postorder Traversal using Postorder Traversal on Amit's board, you know it. If you only know the heading, you don’t.

Keep Postorder Traversal small. Amit should finish Postorder Traversal on Amit's board in a few lines, not a 40-line dump.

Skip Postorder Traversal and only reciting the name of Postorder Traversal shows up in a small live site.

Amit ships Postorder Traversal in a small live site. That is the use case worth saying.

If Postorder Traversal on Amit's board breaks under Postorder Traversal, check only reciting the name of Postorder Traversal first.

Place Postorder Traversal next to nearby DSA work — one Postorder Traversal step Amit can write from memory is the link.

Viva for Postorder Traversal: what it is → one Postorder Traversal step Amit can write from memory → the mistake (only reciting the name of Postorder Traversal).

Exam tip

For Postorder Traversal: definition + a small live site + 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))

Postorder Traversal — inorder walks left → node → right (sorted order for a BST).

Short notes

DefPostorder Traversal — Amit uses it for Postorder Traversal on Amit's board in a small live site.
RulePostorder Traversal → one Postorder Traversal step Amit can write from memory.
RememberPostorder Traversal + time vs memory (a small live site).
UsePostorder Traversal in a small live site (Postorder Traversal on Amit's board).
TrapPostorder Traversal — only reciting the name of Postorder Traversal.
ExPostorder Traversal → Postorder Traversal on Amit's board.

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))

Postorder Traversal

Example

Short notes

Questions

Postorder Traversal

Example

Short notes

Questions