Hands-On Data Structures and Algorithms with Python - Second Edition

Stack implementation

Stacks can be implemented in Python using node. We start off by creating a node class, as we did in the previous chapter with lists:

class Node:     def __init__(self, data=None):         self.data = data         self.next = None 

As we discussed, a node holds data and a reference to the next item in a list. Here, we are going to implement a stack instead of a list; however, the same principle of nodes works here—nodes are linked together through references.

Now let us look at the stack class. It starts off in a similar way to a singly linked list. We will need two things to implement a stack using nodes:

1. We first need to know the node which is at the top of the stack so that we will be able to apply the push and pop operations through ...