DSA · Theory

Find Duplicate Subtrees in Binary Tree

Theory

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Find Duplicate Subtrees in Binary Tree

Amit only reaches for Find Duplicate Subtrees in Binary Tree when folder on disk has to stay correct in a file explorer.

Keep Find Duplicate Subtrees in Binary Tree small. Amit should finish folder on disk in a few lines, not a 40-line dump.

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

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

Don’t do this with Find Duplicate Subtrees in Binary Tree: unbalanced BST becoming a list. Interviewers spot it in ten seconds.

After Find Duplicate Subtrees in Binary Tree, Amit should still remember unbalanced BST becoming a list.

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

Exam tip

Board: folder on disk. Dry-run Find Duplicate Subtrees in Binary Tree. Name the trap: unbalanced BST becoming a list.

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))

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

Short notes

DefFind Duplicate Subtrees in Binary Tree — Amit uses it for folder on disk in a file explorer.
RuleFind Duplicate Subtrees in Binary Tree → left < root < right.
RememberFind Duplicate Subtrees in Binary Tree + a dry-run table (a file explorer).
UseFind Duplicate Subtrees in Binary Tree in a file explorer (folder on disk).
TrapFind Duplicate Subtrees in Binary Tree — unbalanced BST becoming a list.
ExFind Duplicate Subtrees in 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))

Find Duplicate Subtrees in Binary Tree

Example

Short notes

Questions

Find Duplicate Subtrees in Binary Tree

Example

Short notes

Questions