Problems by Difficulty
Choose problems based on your skill level and interview preparation stage.
How to Use This Index
- Beginners (0-1 years): Start with Easy-Medium problems
- Intermediate (2-4 years): Focus on Medium problems
- Advanced (5+ years): Master Hard problems for senior roles
Easy-Medium Problems (5)
Best for: Interview preparation fundamentals, building confidence, learning basic patterns.
Time to solve: 20-35 minutes
- Check if a Linked list is a Palindrome or Not
- Find Longest Palindrome In A String
- Palindromes
- Reverse a doubly linked list
- Reverse a String
Medium Problems (49)
Best for: Most technical interviews at top companies. This is the sweet spot.
Time to solve: 30-45 minutes
Companies: Google, Amazon, Facebook, Microsoft, Apple all ask Medium problems.
- 100 Factorial
- Amazon Interview Question: Count Negative Integers in Matrix
- Bit Manipulation: Essential Tricks and Techniques
- Boolean String Value
- Box ‘o Numbers
- Building a Stack with a getMax() function
- Bumblebee
- Card Trick Without the Trick
- Check If a Number is Power of Two
- Chessboard
- Classic Weighing
- Clock
- Coin Rolls
- Compute X^Y For Floats and Negative Values
- Cube
- Find Out if a Linked List has a Cycle
- Find The Depth of a Binary Tree
- Fruit Jar Problem
- Function that Multiples 2 Integers
- Fuse on Fire
- Getting a fair result with an unfair coin
- Gold Chain
- How many floors can an egg be dropped without breaking?
- Implement a Function to Return a Ratio
- Implement a rate limiter
- Implement LRU Cache
- Implement Trie (Prefix Tree)
- int atoi( char* pStr )
- Kadane’s Algorithm: Maximum Subarray Sum
- Linked List
- Missing country code
- Missing or Duplicate Number in an Array
- Monty Hall Problem
- Prime number problem
- Print String Permutations
- Probability Distribution Function
- Red Marbles, Blue Marbles
- Removing a Character from a String
- Right Rotate an array by k elements
- Server to Process Fair Number of Functions
- Sliding Window Maximum
- Storing 1 million phone numbers
- Sum it Up
- Sum Up a Pair in Array
- Topological Sort
- Treasure Island
- Write a Function for r and 5()
- Write a program for producer-consumer problem
- XOR using NAND gates
Hard Problems (5)
Best for: Senior/Staff engineer roles, demonstrating advanced problem-solving.
Time to solve: 45-60 minutes
Companies: Google L5+, Facebook E5+, Microsoft 64+ often include Hard problems.
