A WORKBENCH FOR YOUR IDEAS

Algorithms you can see.

Write Python. Run a trace. Follow each change, then test the edges.

10 browser labs32 labs in the next app buildNo account · free
01 / Write

Begin with a starter or inspect a worked answer. Your code runs in this browser.

02 / Replay

Play, pause and scrub through real Python state after each line.

03 / Check

Tests cover normal inputs, empty cases, ties and other traps. Progress stays on this device.

Basics

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Prefix Sums

Build cumulative totals, then answer ranges with two lookups

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Data structures

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Monotonic Stack

Resolve waiting days as a warmer temperature arrives

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Algorithms

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Topological Sort

Release tasks as their final prerequisite is removed

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0/1 Knapsack

Fill a capacity table without taking an item twice

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Bellman–Ford

Relax weighted edges and detect reachable negative cycles

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Edit Distance Rows

Compare prefixes with insertion, deletion and substitution

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Machine learning

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Linear Regression

Move a fitted line by following the mean squared-error gradient

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Logistic Regression

Turn a score into a probability and learn a binary boundary

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Nearest Neighbours

Rank points by distance, then vote with explicit tie rules

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Decision Stumps

Try thresholds and choose the lowest weighted Gini impurity

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