Can you create a store class featuring set(Node, value), get(Node), and has(Node) methods for managing Nodes and their values?

Question Analysis

The question asks you to design a Store class that manages nodes and their associated values. The class should feature three methods:

• set(Node, value): This method should allow you to associate a value with a given Node.
• get(Node): This method should retrieve the value associated with a given Node.
• has(Node): This method should check if a given Node is stored in the data structure.

The main challenge here is to decide on an appropriate data structure to manage the nodes and their values efficiently. The problem does not specify the operations' time complexity, but a good solution should strive for efficiency, ideally aiming for average O(1) time complexity for all operations.

Answer

Here is an implementation of the Store class using a dictionary (hash map) to efficiently manage nodes and their values:

class Node:
    def __init__(self, identifier):
        self.identifier = identifier

class Store:
    def __init__(self):
        # Dictionary to store the Node objects and their corresponding values
        self.store = {}

    def set(self, node, value):
        """Associates the given value with the given Node."""
        self.store[node.identifier] = value

    def get(self, node):
        """Retrieves the value associated with the given Node."""
        # Returns None if the node is not found
        return self.store.get(node.identifier, None)

    def has(self, node):
        """Checks if the given Node is in the store."""
        return node.identifier in self.store

# Example usage:

# Create nodes
node1 = Node('node1')
node2 = Node('node2')

# Create store
store = Store()

# Set values
store.set(node1, 'value1')
store.set(node2, 'value2')

# Get values
print(store.get(node1))  # Output: value1
print(store.get(node2))  # Output: value2

# Check if nodes are in the store
print(store.has(node1))  # Output: True
print(store.has(node2))  # Output: True

Key Considerations:

• Efficiency: Using a dictionary allows the set, get, and has operations to run in average O(1) time.
• Node Uniqueness: The Node class uses an identifier attribute as a key for the dictionary. This assumes each node identifier is unique.
• Error Handling: The get method returns None if the node is not found, which is a common convention in Python for indicating a missing value. Adjust this behavior based on your specific needs.