- Executors
-
Learn
Learn Python Runnable examples, NumPy, pandas, and more Learn AINeural networks, ML and LLMs from scratch Learn C & C++ Pointers, memory, STL, and modern C++ Learn C#C# basics, OOP, LINQ, async, and .NET exercises Python Algorithms Search, sorting, recursion, and visualizers O(n) C & C++ Algorithms Compare algorithms implemented in C and C++
- ChallengesNew
Machine learning coding challenges
Practise machine learning with 42 coding challenges, from easy to hard. Every challenge runs in your browser with instant tests, an AI review of your code and community solutions to compare.
Easy · 18 Medium · 20 Hard · 4
Skills you'll practise: Gradient descentBackpropagationChain ruleDecision treesRegressionTransformersActivationsAdamAttentionBPEBanditsBayes' theorem
- Python · C++ · C#
- Automated tests
- AI code review
- Community solutions
- 226
- Challenges
- 2
- Solutions shared
- 3
- Languages
All challenges
Search by topic, language, or difficulty.
Medium
Value Iteration
Compute how valuable each state of a Markov decision process is by repeatedly applying the Bellman optimality update.
You'll learn
Bellman equationMDPs
No solutions yet
Easy
Epsilon-Greedy Multi-Armed Bandit
Balance exploration and exploitation on a multi-armed bandit with epsilon-greedy action selection.
You'll learn
Explore vs exploitBandits
No solutions yet
Medium
Q-Learning Updates
Apply the Q-learning update to a stream of experiences and watch rewards flow back to earlier states.
You'll learn
Q-learningDiscounted rewards
No solutions yet
Medium
Forward Propagation in a Two-Layer Network
Run inputs through a hidden ReLU layer and a sigmoid output layer.
You'll learn
Forward passMulti-layer networks
No solutions yet
Medium
Perceptron Learning Algorithm
Train the original perceptron, which updates its weights only when it makes a mistake.
You'll learn
PerceptronOnline learning
No solutions yet
Easy
Activation Functions
Apply sigmoid, ReLU, Leaky ReLU or tanh to every value in a list.
You'll learn
SigmoidReLU and tanh
No solutions yet
Medium
Gradients of a Single Neuron
Use the chain rule to find how the loss changes with each weight and the bias of a sigmoid neuron.
You'll learn
Chain ruleGradients
No solutions yet
Medium
Layer Normalization
Normalize each row to zero mean and unit variance, then scale and shift it, as every Transformer block does.
You'll learn
Layer normTransformers
No solutions yet
Easy
Loss Functions: MSE, MAE and Cross-Entropy
Measure how wrong a model's predictions are with mean squared error, mean absolute error or binary cross-entropy.
You'll learn
MSECross-entropy
No solutions yet
Hard
Backpropagation in a Two-Layer Network
Compute every weight and bias gradient of a network with one sigmoid hidden layer and one sigmoid output.
You'll learn
BackpropagationChain rule
No solutions yet
Easy
Single Artificial Neuron
Compute the output of one neuron: weighted sum of the inputs plus a bias, passed through sigmoid.
You'll learn
NeuronsWeighted sums
No solutions yet
Easy
Derivatives of Activation Functions
Compute the derivative of sigmoid, ReLU, Leaky ReLU or tanh at each value, the slopes backpropagation needs.
You'll learn
DerivativesBackpropagation
No solutions yet
Medium
Dense Layer Forward Pass
Compute the outputs of a fully connected layer of neurons with a choice of activation.
You'll learn
Dense layersActivations
No solutions yet
Medium
Mini-Batch Gradient Descent
Train a linear model by updating the weights after every small batch of samples instead of the whole dataset.
You'll learn
Mini-batchesGradient descent
No solutions yet
Hard
Multi-Head Self-Attention
Project the input into queries, keys and values, run attention in several heads in parallel, and combine them.
You'll learn
Multi-head attentionMatrix projections
No solutions yet
Easy
Gradient Descent with Momentum
Apply momentum updates, which keep part of the previous step so training speeds up along consistent directions.
You'll learn
MomentumOptimizers
No solutions yet
Easy
Xavier and He Weight Initialization
Compute the range or standard deviation used to initialize the weights of a layer.
You'll learn
Xavier and He initTraining stability
No solutions yet
Medium
Adam Optimizer
Implement Adam, the default optimizer for deep learning, with moving averages and bias correction.
You'll learn
AdamBias correction
No solutions yet
Browse by topic
- Beginner 95
- Ai 47
- Machine Learning 42
- Strings 36
- Arrays 31
- Math 21
- Simulation 19
- Neural Networks 17
- Numbers 16
- Advanced 15
- Dynamic Programming 12
- Parsing 12
- Competitive Programming 10
- Conditions 9
- Design Patterns 8
- Graphs 8
- Grids 8
- Loops 8
- Recursion 7
- Combinatorics 6
- Number Theory 6
- Sorting 6
- Functions 5
- Greedy 5
- Nested Loops 5
- Sequences 5
- Stacks 5
- Variables 5
- Algorithms 4
- Data Structures 4
- Geometry 4
- Patterns 4
- Dictionaries 3
- Fractions 3
- Reinforcement Learning 3
- Sliding Window 3
- Trees 3