What Is M-Way Trees in Data Structure?

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Scott Campbell

In data structure, an M-way tree is a type of multiway tree where each node can have a maximum of M-1 keys and M children. It is also known as an M-ary tree or a K-tree. M-way trees are widely used in computer science for efficient storage and retrieval of data.

Structure of an M-Way Tree

An M-way tree consists of nodes that can have multiple children. Each node in the tree contains a set of keys and pointers to its child nodes. The number of keys in each node determines the order of the tree.

Here is an example to illustrate the structure of an M-way tree:

Node Structure:

• Keys: The values stored in each node, sorted in ascending order.
• Child Pointers: Pointers to the child nodes.

M-Way Tree Properties:

• The root node can have a minimum of 1 key and a maximum of M-1 keys.
• The internal nodes (non-leaf nodes) can have a minimum of ⌈(M-1)/2⌉ keys and a maximum of M-1 keys.
• The leaf nodes contain actual data and can have a minimum of ⌈M/2⌉ – 1 keys and a maximum of M-1 keys.

Operations on M-Way Trees

M-Way trees support various operations such as insertion, deletion, and search. These operations are performed by traversing the tree from the root node to the desired leaf node or internal node.

Insertion

When inserting a new key into an M-way tree, the tree is traversed from the root node until a leaf node is reached. If the leaf node has less than M-1 keys, the new key can be inserted directly. Otherwise, the node is split into two nodes, and the middle key is promoted to the parent node.

Deletion

Deleting a key from an M-way tree involves finding the key in the tree and removing it while maintaining the properties of an M-way tree. If a leaf node has fewer than ⌈M/2⌉ – 1 keys after deletion, redistribution or merging of nodes may be required.

Search

The search operation in an M-way tree follows a similar process to binary search. Starting from the root node, each child pointer is traversed based on whether the desired key is less than or equal to the current key. The search ends when either a matching key is found or a leaf node is reached.