DSA TrainerUnlock the full guided solution
The Prefix Sum walkthrough for Prefix Sum: recognize it cold: the progressive hint ladder, a row-by-row dry run, the optimized code, and an in-browser runner, plus both full courses, DSA and System Design, and every other premium problem.
Already finished Big-O and Hash Maps free? This picks up right where the path leads: same format, harder patterns, the ones that show up in every FAANG-style screen.
What you get
- ✓The full DSA course: concept lessons, drills, graded tests, and cold-read capstones for every pattern
- ✓The full System Design course: 20 building-block units for the design round, included at no extra cost
- ✓Stop going blank on algorithm problems. The hint ladder walks you to the answer without spoiling it.
- ✓Actually internalize the trace: dry runs walk state row by row so it clicks before you write a line
- ✓Know when to reach for each pattern. Every problem names the trigger so you spot it next time.
- ✓Write and run JS or Python in the browser with real test cases on every problem
- ✓Access every new problem, unit, and pattern guide as they ship weekly
“This app finally made it click. I tried NeetCode, CTCI, and YouTube for years and still couldn't solve Two Sum. The beginner mental models for the patterns are genuinely so helpful. THANK YOU.”
Founding Member Deal
$29 / year
or $6 / month
Includes a C++ runner alongside JavaScript and Python.
LeetCode Premium is $159/year and doesn't teach you anything.
Less than one Udemy course, with guided problems instead of passive lectures.
One extra month of job searching costs more than a full year here.
Your price is locked in for life.
Founding rates end when the deal closes. Your rate never changes, no matter how much the curriculum grows.
- ✓Both courses, every unit: DSA + System Design
- ✓All 150 problems across 33 patterns, plus every new one
- ✓New problems and units weekly
- ✓Cancel anytime
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