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Master Python & Data Structures with 199 interactive exercises. Write real code, get instant feedback, zero fluff.

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main.py — CodeRex

Python Basics ◆ Arrays ◆ Linked Lists ◆ Hash Maps ◆ Binary Trees ◆ Recursion ◆ Dynamic Programming ◆ Graphs ◆ Sorting ◆ Stacks & Queues ◆ Two Pointers ◆ Sliding Window ◆ BFS / DFS ◆ Greedy ◆ Backtracking ◆ Python Basics ◆ Arrays ◆ Linked Lists ◆ Hash Maps ◆ Binary Trees ◆ Recursion ◆ Dynamic Programming ◆ Graphs ◆ Sorting ◆ Stacks & Queues ◆ Two Pointers ◆ Sliding Window ◆ BFS / DFS ◆ Greedy ◆ Backtracking ◆

Why CodeRex

Everything you need.
Nothing you don't.

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Live Code Editor

Write Python, hit run, see output. Real execution in your browser with a built-in terminal and REPL.

def two_sum(nums, target):
  seen = {}
  for i, n in enumerate(nums):
    if target - n in seen:
      return [seen[target-n], i]
    seen[n] = i
# → [0, 1]

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DSA Mastery

156 exercises across 24 chapters. Arrays, trees, graphs, DP — every pattern that matters for interviews. LeetCode links included.

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Guided Learning Path

No decision fatigue. Structured chapters build on each other. Rex guides you through every step.

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XP & Progress

Earn XP for every exercise. Track your streak. See how far you've come at a glance.

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Built for Focus

Minimal dark UI, keyboard shortcuts, ADHD-friendly design. No ads, no popups, no social feeds. Just you and the code.

Exercises

Chapters

Courses

Total XP

Curriculum

Start with Python.
Then conquer DSA.

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CUDA Programming

Command an army of thousands of GPU soldiers to solve massive problems in parallel! From absolute zero to GPU mastery — learn CUDA C through a story-driven adventure. Covers GPU architecture, kernels, memory, optimization, and real-world patterns used by AI engineers at top companies.

BEGINNER → ADVANCED →

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C# & .NET Framework

Become a .NET Architect! Master C# from zero to hero through story-driven adventures — variables, OOP, LINQ, async/await, and the mighty .NET ecosystem. Built for interviews, built for fun, built for YOU.

BEGINNER → ADVANCED →

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Data Structures & Algorithms

Master DSA from absolute zero to interview-ready. Covers Big O, arrays, trees, graphs, dynamic programming, and 120+ LeetCode problems — designed so even a kid can start and reach mastery.

BEGINNER → MASTER →

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