Common Python coding questions with difficulty levels

Very Easy

• Print "Hello, World!" in Python

• Check if a number is even or odd

• Concatenate two strings

• Calculate the factorial of a number recursively

• Convert Celsius to Fahrenheit

Easy

• Count the number of vowels in a string

• Find the maximum of three numbers

• Reverse a string

• Check if a string is a palindrome

• Sum elements of a list

• Check if a number is prime

Medium

• Find the first non-repeating character in a string

• Merge two sorted linked lists

• Implement binary search on a sorted array

• Convert Roman numerals to integer

• Detect cycle in a linked list

• Find the longest substring without repeating characters

Hard

• Trapping Rain Water problem

• Word Break problem using Dynamic Programming

• Implement LRU cache

• Median of two sorted arrays

• Find maximum path sum in a binary tree

• Serialize and deserialize a binary tree

Expert

• Implement Trie data structure with insert/search

• Max flow and min cut in a network graph

• Design and implement a distributed cache system

• Solve advanced DP problems like Matrix Chain Multiplication

• Implement concurrent algorithms with Python async or multiprocessing

These cover syntax, data structures, algorithms, and system design coding questions suited for interviewing at various levels, from freshers to senior developers.