AI-coached DSA prep in Java 21. Combines active problem-solving with Spaced Repetition (SRS) to lock in patterns

If this saves you time, a ⭐ on the repo helps others find it.

This repo turns Claude Code into a DSA interview coach. CLAUDE.md defines the coaching rules — it auto-loads every time you run claude in this directory. Commands like /start and /review-dsa are slash commands inside Claude Code, not shell scripts. Your progress lives in notes/REVIEW.md and persists across sessions.

No build step. No server. Just claude in the repo root.

Required

• Claude Code — install via npm install -g @anthropic-ai/claude-code or download the desktop app
• Anthropic account — run claude login once after install

Optional

• Java 21 — only needed if you want to compile/run solutions locally. Claude writes and dry-runs code without it.

git clone https://github.com/dev-vpandey/dsa-prep.git
cd dsa-prep
claude login        # one-time — skips if already logged in
claude              # opens Claude Code with the coaching system loaded
/start              # coach tells you what to work on

Starting fresh? The repo ships with 95 solved problems already in notes/REVIEW.md. To start your own clean slate:

# keep the cheatsheets and templates, wipe the progress tables
echo "# SRS Review Index
| File | Problem | Tag | Stage | Review Date | Last Rating | Review Count | Graduated |
|---|---|---|---|---|---|---|---|" > notes/REVIEW.md

> notes/GRADUATED.md
> notes/GAP-DRILLS.md

Then /start picks a first problem for you.

/start        →  New problem (30–40 min)
/review-dsa   →  Spaced repetition reviews (max 5, ~20 min)

New problem first. Reviews after. Never mix.

╔════════════════╦══════════════════════════════════════════════════════════════╗ ║ Command ║ What it does ║ ╠════════════════╬══════════════════════════════════════════════════════════════╣ ║ /start ║ Finds what to work on next ║ ║ /review-dsa ║ Runs today's SRS review queue (max 5); Sprint Mode Stage 1–2 ║ ║ /pattern X ║ Jump to a specific pattern (e.g. /pattern dp) ║ ║ /retry X ║ Re-attempt a previously solved problem ║ ║ /status ║ Stage distribution + what's overdue ║ ╚════════════════╩══════════════════════════════════════════════════════════════╝

╔══════════════════╦═══════════════════════════════════════════════════════╗ ║ You say ║ You get ║ ╠══════════════════╬═══════════════════════════════════════════════════════╣ ║ hint ║ One-sentence intuition — no algorithm name ║ ║ hint hint ║ Slightly more concrete — still no pattern name ║ ║ hint hint hint ║ Pattern name + relevant cheatsheet section ║ ║ stuck ║ Full Pattern Recognition Framework (SIZE/SHAPE/SMELL) ║ ║ code ║ Full Java 21 solution + dry run + complexity ║ ╚══════════════════╩═══════════════════════════════════════════════════════╝

Claude rates you 1–5 (MAANG interviewer scale), saves a pattern card to notes/[problem]-solved.md, and schedules the next review:

╔══════════╦═════════╦═════════════╦══════════════════════════════════════╗ ║ Rating ║ Stage ║ Next Review ║ Sprint Mode ║ ╠══════════╬═════════╬═════════════╬══════════════════════════════════════╣ ║ 5/5 ║ Stage 3 ║ +7 days ║ Skipped — pattern locked ║ ║ 4/5 ║ Stage 2 ║ +3 days ║ Active for next 2 reviews ║ ║ ≤3/5 ║ Stage 1 ║ +1 day ║ Active for next 2 reviews ║ ╚══════════╩═════════╩═════════════╩══════════════════════════════════════╝

Sprint Mode runs Day+1 and Day+3 reviews as timed recall drills before showing the solution. Say skip, bail, or next to exit Sprint Mode mid-review.

3-Problem Rule: tag matching uses broad/prefix match — two-pointer / in-place and two-pointer / move shorter both count toward two-pointer. If fewer than 3 problems share the root tag, Claude immediately queues the next one from the same pattern. Pattern mastery = 3+ reps.

notes/REVIEW.md                   ←  Master SRS tracking table (source of truth)
notes/GRADUATED.md                ←  Problems cycled out of active review
notes/GAP-DRILLS.md               ←  Pattern gap tracker — muscle vs conceptual drills
notes/[problem]-solved.md         ←  Pattern cards for every solved problem (95+)
notes/cheatsheets/                ←  8 pattern group cheatsheets + keyword index
templates/post-solve-checklist.md ←  Post-solve procedure (card, SRS, cheatsheet sync)

GAP-DRILLS.md — when a review surfaces a weak pattern, the coach logs it here with a targeted drill. Two types: Muscle (write boilerplate cold) and Conceptual (fresh unseen problem). Rows close once the pattern is strong.

GRADUATED.md — problems that have reached Stage 6 (90-day interval) move here. They re-enter active review if a future problem surfaces the same pattern as weak.

GPL-3.0 — see LICENSE.