Coding Challenges

Explore our comprehensive collection of coding challenges across various domains. Practice, learn, and master different aspects of programming.

Easy

Two Sum

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

Arrays
Hash Table
Coming Soon
Medium

Merge Intervals

Given a collection of intervals, merge all overlapping intervals.

Arrays
Sorting
Coming Soon
Medium

Longest Substring Without Repeating Characters

Find the length of the longest substring without repeating characters.

String
Sliding Window
Hash Table
Coming Soon
Hard

Median of Two Sorted Arrays

Find the median of the two sorted arrays.

Arrays
Binary Search
Divide and Conquer
Coming Soon
Easy

Valid Parentheses

Determine if the input string has valid parentheses.

String
Stack
Coming Soon
Medium

LRU Cache

Design and implement a data structure for Least Recently Used (LRU) cache.

Design
Hash Table
Linked List
Coming Soon
Easy

Implement a Stack

Implement a stack data structure with push, pop, top, and getMin operations.

Stack
Design
Coming Soon
Medium

Binary Tree Level Order Traversal

Given a binary tree, return the level order traversal of its nodes' values.

Tree
BFS
Coming Soon
Medium

Implement a Trie

Implement a trie with insert, search, and startsWith methods.

Trie
Design
Coming Soon
Hard

Serialize and Deserialize Binary Tree

Design an algorithm to serialize and deserialize a binary tree.

Tree
DFS
Design
Coming Soon
Medium

Implement a Graph

Implement a graph data structure with basic operations.

Graph
Design
Coming Soon
Beginner

Linear Regression from Scratch

Implement linear regression algorithm without using ML libraries.

Regression
NumPy
Medium

K-Means Clustering

Implement the K-means clustering algorithm from scratch.

Clustering
Unsupervised Learning
Coming Soon
Medium

Decision Tree Implementation

Build a decision tree classifier from scratch.

Classification
Tree
Coming Soon
Hard

Neural Network from Scratch

Implement a simple neural network with backpropagation.

Neural Networks
Deep Learning
Coming Soon
Medium

PCA Implementation

Implement Principal Component Analysis from scratch.

Dimensionality Reduction
Linear Algebra
Coming Soon
Medium

Naive Bayes Classifier

Implement a Naive Bayes classifier for text classification.

Classification
Probability
NLP
Medium

Content-Based Recommendation System

Design a content-based recommendation system for a streaming platform.

Recommendation Systems
Feature Engineering
Similarity Metrics
Coming Soon
Hard

Real-time Fraud Detection System

Design a real-time fraud detection system for financial transactions.

Anomaly Detection
Real-time Processing
Feature Engineering
Coming Soon
Hard

Search Ranking System

Design a search ranking system for a large-scale e-commerce platform.

Information Retrieval
Ranking
Relevance Scoring
Coming Soon
Medium

Ad Click Prediction System

Design a system to predict ad clicks in real-time for an advertising platform.

Click Prediction
Online Learning
Feature Engineering
Coming Soon
Hard

Large-Scale Image Recognition Service

Design a scalable image recognition service that can handle millions of requests per day.

Computer Vision
Scalability
Model Serving
Coming Soon
Medium

ML Feature Store

Design a feature store for machine learning features that supports both online and offline access.

Feature Store
MLOps
Data Engineering