Python Data Structures and Algorithms interview questions

Here are some Python data structures and algorithms interview questions along with their answers:

What is the difference between a list and a tuple in Python?

A list is a mutable data structure, which means its elements can be modified after creation. In contrast, a tuple is immutable, and its elements cannot be changed once defined.

Explain the concept of time complexity and space complexity.

Time complexity refers to the amount of time taken by an algorithm to run as a function of the input size. It provides an estimate of how the algorithm's running time grows with respect to the input size.

Space complexity refers to the amount of memory required by an algorithm to run as a function of the input size. It estimates how the algorithm's memory usage grows with respect to the input size.

What is the difference between a stack and a queue?

A stack is a Last-In-First-Out (LIFO) data structure, meaning that the last element added is the first one to be removed.

A queue is a First-In-First-Out (FIFO) data structure, where the element added first is the first one to be removed.

Explain the concept of Big O notation.

Big O notation is used to describe the performance or complexity of an algorithm. It represents the upper bound or worst-case scenario of how the algorithm's time or space requirements grow with respect to the input size.

For example, if an algorithm has a time complexity of O(n), it means that the running time grows linearly with the input size.

What is a hash table in Python?

A hash table, also known as a dictionary or associative array, is a data structure that allows efficient insertion, deletion, and retrieval of key-value pairs.

Python's built-in dictionary is an implementation of a hash table, where the keys are hashed to compute their storage location in memory.

What is the difference between a shallow copy and a deep copy?

A shallow copy creates a new object that references the original elements. Modifying the elements of a shallow copy will affect the original object as well.

A deep copy creates a new object and recursively copies the elements of the original object. Modifying the elements of a deep copy does not affect the original object.

What is the difference between a binary search and a linear search?

A linear search checks each element in a collection until it finds the target element or reaches the end. It has a time complexity of O(n) in the worst case.

A binary search, on the other hand, is a more efficient search algorithm for sorted collections. It repeatedly divides the search space in half, discarding the half that doesn't contain the target element. It has a time complexity of O(log n) in the worst case.

Explain the concept of recursion and provide an example.

Recursion is a programming technique where a function calls itself directly or indirectly to solve a problem by breaking it down into smaller subproblems.

Example:

Python Copy code

def factorial(n):

    if n == 0:

        return 1

    else:

        return n * factorial(n - 1)

print(factorial(5))  # Output: 120

What is the difference between a linked list and an array?

An array is a collection of elements stored in contiguous memory locations, allowing direct access to elements using an index. Arrays have a fixed size.

A linked list is a collection of nodes where each node contains a value and a reference to the next node.

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