Computer Science
Programming Fundamentals Challenges
Programming Fundamentals challenges put you inside the work of writing code that is correct, readable and fast. You'll build core skills in functions & data structures, object-oriented design and design patterns, work in Python or JavaScript, and learn to do code reading and refactoring the way teams expect.
From there you'll tackle the harder edges — algorithm analysis, complexity analysis, graph algorithms and generics & type systems — pushing into performance engineering, low-latency programming patterns and systems-language proficiency (Go, Rust, C++). Each challenge you solve earns a verified credential you can share with recruiters.
- AnalysisBeginnerNew
Approximate Inference for a Topic Model on Customer Tickets
You receive 180,000 tickets (subject + body) spanning the last 18 months. Preprocess into a bag-of-words representation with sensible stopwords and bigrams. Fit a 20-topic LDA v…
- Variational Inference
- Latent Dirichlet Allocation
- Approximate Inference
Open coursework - CodeIntermediateNew
Reason over a Climate Policy Knowledge Graph for an EU Think Tank
Design a knowledge graph schema covering regulations, member states, sectors, transposition dates, and source-document citations. Ingest a curated dataset of around 200 nodes th…
- Knowledge Graphs
- Knowledge Representation
- Rule Based Reasoning
Artificial Intelligence: Principles and Techniques - CodeIntermediateNew
Refactor a God-Object Order Service with Strategy + Command
Read OrderService and the last 18 months of bug tickets touching it. Author a 5-page design document showing the current class diagram, the target Strategy-per-order-type + Comm…
- Design Patterns
- Refactoring
- Strategy Pattern
Software Design and Design Patterns - CodeIntermediateNew
Design a Force-Controlled Polishing Skill for a Watchmaker
You receive simulated polishing trajectories from the manufacturer's robot, force-sensor logs from 20 master-craftsman demonstrations, and a quality-rubric (mirror finish 1-5) f…
- Impedance Control
- Force Control
- Manipulation
Robotics Practice your coursework on real scenarios.
Every challenge is shaped from real-world context — not generic exercises. The work mirrors what your degree prepares you for.
Why Ewance
- AnalysisBeginnerNew
Audit a Hiring-Screening Model for Demographic Bias
You receive: (a) inference API access to the production model (black-box), (b) a 12,000-resume audit benchmark with self-declared gender and age-band labels (consented, GDPR-com…
- Fairness Metrics
- Bias Auditing
- Model Evaluation
AI Ethics, Fairness, and Responsible AI - CodeBeginnerNew
Forecast Hourly Energy Demand for a Microgrid Operator
You receive 24 months of hourly demand, weather (temperature, irradiance), and calendar data for the community. Build a probabilistic forecaster (e.g., quantile regression with …
- Probabilistic Forecasting
- Quantile Regression
- Deep Forecasting
Open coursework - CodeIntermediateNew
Simulating Queueing for a 40-Person SaaS Support Team
Build a discrete-event simulation of the ticket handling process: tickets arrive randomly (Poisson), are triaged, then assigned to specialists (tier 1 and tier 2). Calibrate usi…
- Simulation
- Queueing Theory
- Python
Operations Analytics and Optimization - CodeSeniorNew
Implement a Proof-of-Stake Consensus Mechanism in Rust
Read the Casper FFG paper (Buterin + Griffith, 2017) and design a simplified PoS implementation in Rust: 21 validators, 32-slot epochs, two-phase finality (justify, then finaliz…
- Consensus Algorithms
- Blockchain Protocols
- Rust
Blockchain and Decentralized Systems Engineering - Browse challenges
Explore role
Marketing Analyst
Plan and measure campaigns that grow the business. Funnel analytics, attribution, segmentation, and the rigorous measurement that lets marketing defend its budget at the leadership table.
- CodeBeginnerNew
Demand Sensing for a 40-Person SaaS Scale-Up
You are a growth analyst at FlowMetrics. Using weekly data on signups, trial conversions, website traffic, and marketing spend, develop a model to forecast monthly subscription …
- Time Series Forecasting
- Regression Analysis
- Python
Forecasting for Decision Making - CodeIntermediateNew
Refactor a Big-Ball-of-Mud Java Servlet Application
Week 1: install JUnit 5 + Testcontainers harness, write characterization tests for the 2 target workflows (PolicyIssue + ClaimSubmit) reaching at least 80 percent branch coverag…
- Refactoring
- Characterization Testing
- Legacy Systems
Software Evolution and Maintenance - AnalysisBeginnerNew
Audit a Climate-Tech Sensor Dataset for Production Readiness
You receive 18 months of raw sensor readings from 1,200 sensors (about 800M rows), plus a sensor-metadata table (location, firmware version, deployment date). Profile the data f…
- Data Quality Audit
- Data Profiling
- Time Series Analysis
Applied Data Analysis and Practical Data Science - CodeIntermediateNew
Code Review and Refactoring of a Legacy E-Commerce Module
You are given a codebase (Java/Spring Boot) of the order module. Perform a static analysis, document issues (e.g., god classes, tight coupling), and write a refactoring proposal…
- Code Review
- Refactoring
- Java
Open coursework Build a verifiable portfolio.
Submissions become evidence. Reviewers with shipping experience score against a rubric; the result becomes a credential anyone can verify.
Why Ewance
- CodeIntermediateNew
Apply the Mikado Method to Untangle a Tax-Engine Class
Starting from the live codebase (Java 17, 73 percent line coverage), write a failing test that asserts the desired end state ('TaxCalculator is decomposed into per-country strat…
- Mikado Method
- Refactoring
- Strategy Pattern
Refactoring and Code Smell Detection - AnalysisIntermediateNew
Run a Pre-Deployment Fairness + Drift Audit on a Hiring Model
You receive a trained classifier (joblib), the training data sample, and a held-out 'next-month' evaluation set. Compute group fairness metrics (false-positive-rate gap, true-po…
- Fairness Metrics
- Drift Detection
- Bias Mitigation
Machine Learning in Practice - AnalysisIntermediateNew
Optimize Stop-Loss Policies with Dynamic Programming at a Quant Fund
You receive five years of daily PnL series for 12 momentum strategies plus a small set of state features (rolling vol, drawdown, regime indicator). Calibrate a discrete Markov m…
- Dynamic Programming
- Backward Induction
- State Modeling
Open coursework - AnalysisBeginnerNew
Profile and Optimize a Virtual-Memory-Heavy Image Pipeline
Receive the Go pipeline source, a representative batch (1,200 photos averaging 12MB each, with 30 outliers over 80MB), and host specs (4-core, 16GB RAM, Linux kernel 5.15). Run …
- Virtual Memory
- Performance Profiling
- Memory Hierarchy
Open coursework - CodeBeginnerNew
Build a Crawler-and-Topic Pipeline for Public-Sector Web Analytics
You will build a polite, robots.txt-respecting crawler that ingests about 30,000 new posts/week across the 80 forums into a normalized dataset. Apply a topic model (BERTopic, wi…
- Web Crawling
- Topic Modeling
- NLP Pipeline
Open coursework - CodeBeginnerNew
Build a Face-Anonymization Tool for a Civic-Tech Newsroom
Use a pretrained face detector (RetinaFace or YOLOv8-face is fine). Build a Python tool with a Gradio or Streamlit UI that: (1) detects faces in an uploaded photo, (2) shows det…
- Object Detection
- Image Processing
- Opencv
Open coursework - DesignIntermediateNew
Add Profile-Guided Optimization to a Production JavaScript Bundler
Design and implement a profile-guided optimization workflow for the bundler using Rust's LLVM-based PGO: an instrumented build, a training run over the eight-project benchmark c…
- Profile Guided Optimization
- Llvm
- Benchmarking
Open coursework - CodeBeginnerNew
Responsive Web Redesign for SaaS Scale-up
You are to redesign the TaskFlow website's homepage, pricing page, and a new 'Enterprise' landing page. The redesign must be responsive (mobile-first) and built with HTML/CSS/JS…
- Html
- Css
- Javascript
Open coursework - ResearchSeniorNew
Benchmark Conformal Prediction for a Healthcare Risk-Score
You receive a labeled dataset of about 25,000 patient encounters with the current risk-score's predictions and ground-truth 1-year outcomes. Implement and compare split conforma…
- Conformal Prediction
- Uncertainty Quantification
- Calibration
Statistical Machine Learning - AnalysisIntermediateNew
Evaluate an Agent Suite on the SWE-Bench-Style Coding Benchmark
You receive a sandboxed set of 50 small repo-modification tasks (test-passing as the success signal). Run 3 open-source agent frameworks (e.g., OpenHands, SWE-agent, and Aider) …
- LLM Agents
- Agent Evaluation
- Benchmarking
Open coursework - CodeSeniorNew
Survival-Analysis Risk Model for an Oncology Decision-Support Pilot
You receive a curated public colorectal cancer cohort (about 9,000 patients, demographics, stage, grade, comorbidities, baseline labs, censored survival times). Fit (1) a Cox pr…
- Survival Analysis
- Risk Stratification
- Model Calibration
Machine Learning for Healthcare and Biomedicine - CodeIntermediateNew
Build a GraphQL Federation Schema for an E-Commerce Platform
Receive the existing 22 REST endpoints' OpenAPI specs and a list of 5 priority subgraphs. Design a federated GraphQL schema using Apollo Federation v2 directives (@key, @externa…
- Graphql
- Graphql Federation
- API Design
API Design and GraphQL
How it works
From brief to credential, in six steps.
Step 01
Browse challenges aligned to your studies.
Step 02
Accept the one that fits your goals.
Step 03
Work through it with AI Copilot guidance.
Step 04
Submit for structured evaluation.
Step 05
Earn a verified credential.
Step 06
Add it to LinkedIn with one click.
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