Fixes the bug where a specialization could show "Achievable" while no per-set ceiling cell surfaces a path to it. Reproduction: pin SP2=Business of Health & Medical Care, SP4=Foundations of Fintech, SP5=Corporate Finance, SE1=GIE; rank HCR first. Healthcare showed Achievable but every ceiling cell excluded HCR. Root cause: computeCeiling used strict > on count alone, so the first equal-count combination found won permanently and HCR-including outcomes were never recorded. Changes: - Replace per-(set, choice) computeCeiling loop with a single full-tree searchDecisionTree DFS. Both the per-set ceiling table and a new ranked top-K plan list (default K=10) are populated from one enumeration. - Comparison rule everywhere is (count desc, priority score desc, deterministic-tiebreak). priorityScore extracted from optimizer.ts into a shared priority.ts module used by both call sites. - Heuristic enumeration ordering: select the first reachable ranked spec as priorityTarget; reorder DFS children at every level so target- qualifying courses are tried first. High-priority outcomes surface in early iterations instead of being blocked by less-relevant equal-count results. - Bounded search: terminate on saturation (top-K stable for 500 iterations) or hard cap (10000 iterations); set partial=true if cap hit. Mitigates the worst-case enumeration cost. - Worker protocol: tagged-union response with topKUpdate, choiceUpdate (per-cell, replaces per-set setComplete), and allComplete events. - App state adds topPlans/topPlansPartial slices and an adoptPlan action that pins a plan's full course assignment in one click. Also fixes loadState's stale "ranking.length !== 14" check (now uses SPECIALIZATIONS.length so HCR-era saved state restores correctly). - New TopPlans component renders the ranked list with adopt buttons, placed above CourseSelection in the right column. - 17 new tests in searchDecisionTree.test.ts covering priority scoring, bounded ranked list, comparison rule, target selection, the user's reproduction scenario, streaming monotonicity, saturation termination, and a performance smoke test (< 5s for the 8-open-set case). - Existing decisionTree.test.ts: one test amended for per-cell streaming semantics; remaining 3 unchanged and passing.
EMBA Specialization Solver
A client-side web application that helps EMBA students optimize their elective course selections to maximize the number of specializations they can earn.
The Problem
The J27 EMBA program offers 46 elective courses across 12 elective sets (Spring, Summer, Fall terms). Students select one course per set — 12 electives total, 30 credits. The program defines 14 specializations, each requiring 9+ credits (at least 4 qualifying courses). The catch: course credits do not duplicate across specializations. When a course qualifies for multiple specializations, its 2.5 credits must be allocated (potentially split) among them. This makes course selection a non-trivial credit allocation optimization problem.
Key constraints:
- Credit sharing: Each course's 2.5 credits are split across qualifying specializations — no double-counting
- Maximum 3 specializations: 12 courses × 2.5 credits = 30 total, and 3 × 9 = 27, so 3 is the theoretical max
- Required courses: 4 specializations require a specific course to be selected
- Strategy S1/S2 tiers: The Strategy specialization limits S2-marked courses to at most 1 contributing
Features
- Two optimization modes:
- Maximize Count — finds the largest set of achievable specializations, using ranking as a tiebreaker
- Priority Order — processes specializations in your ranked order, greedily adding each if feasible
- Drag-and-drop ranking — reorder specializations by priority
- Live optimization — results update instantly as you select courses
- Decision tree analysis — a Web Worker enumerates remaining course combinations to show ceiling outcomes per choice (how many specializations each option can lead to)
- Status tracking — each specialization is classified as achieved, achievable, missing a required course, or unreachable
- Mode comparison — shows what the alternative mode would produce so you can pick the better result
- Responsive — mobile layout with floating status banners
- State persistence — selections and rankings saved to localStorage
Tech Stack
- React 19 + TypeScript
- Vite 7 (dev server, bundler)
- javascript-lp-solver — linear programming for credit allocation feasibility checks
- @dnd-kit — drag-and-drop for specialization ranking
- Vitest — test runner
- Nginx — production static file server (Docker)
Prerequisites
- Node.js >= 22
- npm
- Docker and Docker Compose (for containerized deployment)
Development
All commands run from the app/ directory:
cd app
Install dependencies
npm install
Start the dev server
npm run dev
The app will be available at http://localhost:5173 with hot module replacement.
Run tests
npm test
Or in watch mode:
npm run test:watch
Lint
npm run lint
Build for production
npm run build
Output goes to app/dist/.
Preview production build locally
npm run preview
Deployment
Docker Compose (recommended)
From the project root:
docker compose up -d
This builds a multi-stage Docker image:
- Build stage — installs dependencies and runs
vite buildin a Node 22 Alpine container - Serve stage — copies the built static files into an Nginx Alpine container
The app is served on port 8080 by default. Override with the PORT environment variable:
PORT=3000 docker compose up -d
Docker (standalone)
docker build -t emba-solver .
docker run -p 8080:80 emba-solver
Static hosting
Run npm run build in app/ and deploy the app/dist/ directory to any static file host (Netlify, Vercel, S3, GitHub Pages, etc.). The app is fully client-side with no backend dependencies.
Project Structure
├── Dockerfile # Multi-stage build (Node → Nginx)
├── docker-compose.yml # Single-service compose config
├── nginx.conf # Nginx config with gzip, caching, SPA fallback
└── app/ # Vite + React application
├── src/
│ ├── main.tsx # Entry point
│ ├── App.tsx # Root component
│ ├── data/ # Static course/specialization data
│ │ ├── types.ts # TypeScript interfaces
│ │ ├── courses.ts # 46 courses with qualifications
│ │ ├── electiveSets.ts # 12 elective sets
│ │ ├── specializations.ts # 14 specializations
│ │ └── lookups.ts # Derived indexes
│ ├── solver/ # Optimization engine
│ │ ├── optimizer.ts # Maximize-count & priority-order modes
│ │ ├── feasibility.ts # LP-based feasibility checks
│ │ └── decisionTree.ts # Exhaustive ceiling analysis
│ ├── components/ # UI components
│ ├── state/ # App state (useReducer + localStorage)
│ ├── hooks/ # Custom hooks (useMediaQuery)
│ └── workers/ # Web Worker for decision tree
└── vite.config.ts
How the Solver Works
- Feasibility checking — uses a linear program (LP) to determine whether a target set of specializations can each reach 9 credits given the selected courses, respecting per-course capacity (2.5 max) and the Strategy S2 constraint
- Maximize Count — tries all combinations of candidate specializations from size 3 down to 1, checking LP feasibility for each; among equal-size feasible sets, picks the one with the highest priority score based on ranking
- Priority Order — iterates specializations in rank order, greedily adding each to the achieved set if the combined set remains LP-feasible
- Decision tree — for each open (unselected) elective set, enumerates all possible remaining course combinations to compute the best-case outcome per choice, helping users identify which selections matter most