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C# coding challenges
226 challenges you can solve in C#, from first loops to graphs, dynamic programming and machine learning. Write your code in the browser, run the tests instantly and get an AI review.
Easy · 134 Medium · 68 Hard · 24
Skills you'll practise: CountingDigit extractionString splitting2D listsArithmeticFormulasListsLoopsConditionsDivisibilityFloating pointGradient descent
- Python · C++ · C#
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- 226
- Challenges
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All challenges
Search by topic, language, or difficulty.
Easy
Hamming Distance
Compare two DNA strings position by position and count the differences.
You'll learn
String comparisonCounting
No solutions yet
Easy
Move Zeroes
Move every zero to the end while keeping the other order.
You'll learn
Two pointersIn-place updates
No solutions yet
Easy
Rotate Array
Rotate a list to the right by some steps.
You'll learn
Array indexingModulo
No solutions yet
Easy
Running Sum
Replace each value with the total so far.
You'll learn
Prefix sumsLists
No solutions yet
Medium
Right-Triangle Product
Find the largest side product of an integer right triangle with a given perimeter.
You'll learn
Right trianglesSearch pruning
No solutions yet
Medium
Flatten Arbitrarily Nested Lists (Recursion)
Practice recursion by flattening arbitrarily nested lists while skipping null entries.
You'll learn
Base casesNested data
No solutions yet
Medium
Minimax Tic-Tac-Toe
Pick the perfect tic-tac-toe move by searching the whole game tree with minimax.
You'll learn
MinimaxGame trees
No solutions yet
Medium
Largest Adjacent-Digit Product
Take every contiguous window of span digits and multiply its digits.
You'll learn
Fixed-size windowsDigit strings
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
Count Words
Count the words in a sentence.
You'll learn
String splittingWhitespace
No solutions yet
Easy
Classify a Number by Its Divisors
Classify a positive integer as perfect, abundant, or deficient.
You'll learn
DivisorsClassification
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
Hard
Train a Neural Network to Solve XOR
Combine everything: train a 2-2-1 sigmoid network with backpropagation until it learns XOR.
You'll learn
Neural network trainingXOR problem
No solutions yet
Easy
Difference of Squares
Subtract the sum of squares from the square of the sum.
You'll learn
FormulasArithmetic
No solutions yet
Easy
Pascal’s Triangle
Build rows by adding neighboring entries from the previous row.
You'll learn
2D listsBuilding from previous rows
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
Easy
Chess Square Color
Determine the color of a square on an 8 by 8 board.
You'll learn
CoordinatesParity
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
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