🌱 Insertion in Binary Search Tree (BST)

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🔹 Rule:

Insert a new node by comparing it with the current node:

• If smaller → go to left

• If larger → go to right

• Repeat until a null spot is found

📘 Example:

Let's insert the following values in this order:

50 → 30 → 70 → 20 → 40 → 60 → 80

🔧 Step-by-Step Insertion:

1. Insert 50 → becomes root

2. Insert 30 → 30 < 50 → go left

3. Insert 70 → 70 > 50 → go right

4. Insert 20 → 20 < 50 → left → 20 < 30 → left

5. Insert 40 → 40 < 50 → left → 40 > 30 → right

6. Insert 60 → 60 > 50 → right → 60 < 70 → left

7. Insert 80 → 80 > 50 → right → 80 > 70 → right

🌳 Final BST Diagram:

50 / \ 30 70 / \ / \ 20 40 60 80

🧠 Python Code:

class Node: def __init__(self, key): self.left = self.right = None self.val = key def insert(root, key): if root is None: return Node(key) if key < root.val: root.left = insert(root.left, key) else: root.right = insert(root.right, key) return root # Insert nodes root = Node(50) for key in [30, 70, 20, 40, 60, 80]: insert(root, key)

✅ Tip:

Always start from the root, compare, and go left/right until an empty spot is found.