CodeBaobab

The grind is broken; grow deep roots and lasting skills.

Prepare for technical interviews with guided courses and practice. Build data science and ML skills with real-world projects.

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Build step by step

Learning staircase: Algorithms

Build the foundations, then combine them to solve more advanced problems.

Selected topics. Step heights illustrate learning order, not measured difficulty or performance.

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What would you like to learn?

Start with a course, or apply your skills in a project.

Algorithms

Progressive data structures and algorithms for technical interviews.

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Data Science & Machine Learning

Python, probability, modeling, experimentation, AI, and reinforcement learning.

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SQL & Data

Learn SQL through step-by-step examples, with pandas comparisons.

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Projects

Build data science and ML skills by exploring messy, realistic data and solving real-world problems.

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Example preview

See how learning turns into practice.

Illustrative snippets and progress, not your saved activity.

LearnHash Tables and SetsPracticeContains Duplicate

Contains Duplicate

You are given an integer array nums. Return true if any value appears more than once.

def contains_duplicate(nums):
seen = set()
for num in nums:
if num in seen:
return True
seen.add(num)
return False
✓ 3 / 3 tests passed
Example progress
  • Hash Tables and Sets
  • Set Membership
  • Contains Duplicate
  • Frequency Maps
Explore Algorithms
Learning philosophy

Strong foundations. Skills that grow.

Like the baobab tree, lasting skill grows from the roots up—master the fundamentals first, and every harder topic has something to hold onto.

Learn one idea, practice it, then build on it. The baobab represents that progression: roots, trunk, and branches.

  1. Root
    Build the foundations

    Start with the essential ideas in your chosen course.

  2. Trunk
    Strengthen reusable patterns

    Ideas you can recognize and reproduce under pressure.

  3. Branch
    Solve what you have not seen

    Progressive problems turn understanding into independence.

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