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Searching in BST

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Searching in BST

Don’t start Searching in BST with jargon. Start with folder on disk. That is the whole point.

For Searching in BST, Big-O is in play. Don’t blame it until you have traced folder on disk.

Without Searching in BST, a file explorer gets messy and folder on disk is hard to trust.

Neha ships Searching in BST in a file explorer. That is the use case worth saying.

Don’t do this with Searching in BST — unbalanced BST becoming a list. Interviewers spot it in ten seconds.

After Searching in BST, Neha should still remember unbalanced BST becoming a list.

Close Searching in BST with — “If I skip it, folder on disk goes wrong like this: unbalanced BST becoming a list.”

Diagram

Exam tip

Say Searching in BST in one breath, then left < root < right, then unbalanced BST becoming a list.

Example

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

def insert(root, val):
    if root is None:
        return Node(val)
    if val < root.val:
        root.left = insert(root.left, val)
    elif val > root.val:
        root.right = insert(root.right, val)
    return root

root = None
for v in [5, 2, 7, 1]:
    root = insert(root, v)
print(root.val, root.left.val, root.right.val)

Searching in BST — bST invariant: left < node < right — enables log-time search when balanced.

Short notes

DefSearching in BST — Neha uses it for folder on disk in a file explorer.
RuleSearching in BST → left < root < right.
RememberSearching in BST + Big-O (a file explorer).
UseSearching in BST in a file explorer (folder on disk).
TrapSearching in BST — unbalanced BST becoming a list.
ExSearching in BST → folder on disk.

class Node: def __init__(self, val): self.val = val self.left = None self.right = None def insert(root, val): if root is None: return Node(val) if val < root.val: root.left = insert(root.left, val) elif val > root.val: root.right = insert(root.right, val) return root root = None for v in [5, 2, 7, 1]: root = insert(root, v) print(root.val, root.left.val, root.right.val)

Searching in BST

Example

Short notes

Questions

Searching in BST

Example

Short notes

Questions