Code challenge solution - Nguyen Quang Duc

readme.md

@@ -1,10 +1,3 @@
-# 99Tech Code Challenge #1 #
-
-Note that if you fork this repository, your responses may be publicly linked to this repo.  
-Please submit your application along with the solutions attached or linked.   
-
-It is important that you minimally attempt the problems, even if you do not arrive at a working solution.
-
-## Submission ##
-You can either provide a link to an online repository, attach the solution in your application, or whichever method you prefer.
-We're cool as long as we can view your solution without any pain.
+## Instructions to Run Projects
+Each project inside this repository contains its own README with setup and run instructions.
+Please refer to the respective project folder for details.

src/problem4/problem4.js

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+
+// Time complexity: O(n)
+// Space complexity: O(1)
+function sum_to_n_a(n: number): number {
+  let sum = 0;
+
+  for (let i = 1; i <= n; i++) {
+    sum += i;
+  }
+
+  return sum;
+}
+
+
+// Time complexity: O(1)
+// Space complexity: O(1)
+function sum_to_n_b(n: number): number {
+  return (n * (n + 1)) / 2;
+}
+
+
+// Time complexity: O(n)
+// Space complexity: O(n)
+function sum_to_n_c(n: number): number {
+  const memo = {};
+
+  function sum(x: number): number {
+    if (x <= 1) return x;
+    if (memo[x] !== undefined) return memo[x];
+
+    memo[x] = x + sum(x - 1);
+    return memo[x];
+  }
+
+  return sum(n);
+}

src/problem5/backend-game-inventory/.dockerignore

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+node_modules
+dist
+.git
+.env

src/problem5/backend-game-inventory/.env.example

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+MONGO_URI=mongodb://db:27017/game_inventory
+PORT=3000
+NODE_ENV=development

src/problem5/backend-game-inventory/.gitignore

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+node_modules
+# Keep environment variables out of version control
+.env
+dist

src/problem5/backend-game-inventory/README.md

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+# Game Inventory API
+
+A simple **Game Inventory Management API** built with **Node.js, Express, TypeScript, MongoDB, and Docker**.
+
+---
+
+# Tech Stack
+
+- Node.js + Express
+- TypeScript
+- MongoDB
+- Docker & Docker Compose
+
+---
+
+# Project Structure
+```bash
+├── app.ts
+├── server.ts
+│
+├── config
+│ ├── env.ts
+│ └── index.ts
+│
+├── controllers
+│ ├── game.controller.ts
+│ └── tests
+│
+├── services
+│ ├── game.service.ts
+│ └── tests
+│
+├── routes
+│ └── game.routes.ts
+│
+├── models
+│ └── game.model.ts
+│
+├── db
+│ └── mongo.ts
+│
+├── dto
+│ └── game.dto.ts
+│
+├── validation
+│ └── game.validation.ts
+│
+├── middleware
+│ ├── errorHandler.ts
+│ └── validate.ts
+│
+├── utils
+│ ├── AppError.ts
+│ ├── asyncWrapper.ts
+│ ├── errors.ts
+│ ├── handler.ts
+│ └── response.ts
+│
+├── types
+│ ├── express.d.ts
+│ └── validated-request.ts
+│
+└── docs
+└── openapi.yaml
+```
+
+# Environment Setup
+
+## 1. Create `.env` file
+
+Copy from `.env.example`:
+
+```bash
+cp .env.example .env
+```
+Example
+```
+PORT=3000
+MONGO_URI=mongodb://db:27017/game_inventory
+NODE_ENV=development
+```
+
+## 2. Development setup
+
+Start dev environment
+```bash
+docker compose -f docker-compose.dev.yml up -d
+```
+
+View logs
+```bash
+docker compose -f docker-compose.dev.yml logs -f app
+```
+Access app
+```
+http://localhost:3000
+```
+
+Stop dev
+```bash
+docker compose -f docker-compose.dev.yml down
+```
+
+## 3. Production setup
+
+Start production
+```bash
+docker compose -f docker-compose.prod.yml up -d --build
+```
+
+View logs
+```bash
+docker compose -f docker-compose.prod.yml logs -f app
+```
+
+Access app
+```
+http://localhost:3000
+```
+
+Stop production
+```bash
+docker compose -f docker-compose.prod.yml down
+```
+
+## 4. API Documentation
+
+The API is documented using OpenAPI (Swagger).
+
+After running the application, you can access the API documentation at:
+
+```
+http://localhost:3000/api-docs
+```
+
+## 5. Running Tests
+
+The project uses Jest for unit testing.
+
+Run all tests
+```
+npm run test
+```
+
+Run tests in watch mode
+```
+npm run test:watch
+```

src/problem5/backend-game-inventory/docker-compose.dev.yml

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+version: "3.9"
+
+services:
+  db:
+    image: mongo:7
+    container_name: game-mongo
+    ports:
+      - "27017:27017"
+    volumes:
+      - mongo_data:/data/db
+
+  app:
+    build:
+      context: . 
+      dockerfile: docker/Dockerfile.dev
+    container_name: game-api
+    depends_on:
+      - db
+    ports:
+      - "3000:3000"
+    env_file:
+      - .env
+    volumes:
+      - .:/app
+      - /app/node_modules
+    environment:
+      CHOKIDAR_USEPOLLING: "true"
+    command: sh -c "npm run seed && npm run dev"
+
+volumes:
+  mongo_data:

src/problem5/backend-game-inventory/docker-compose.prod.yml

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+version: "3.9"
+
+services:
+  db:
+    image: mongo:7
+    container_name: game-mongo
+    restart: always
+    volumes:
+      - mongo_data:/data/db
+
+  app:
+    build:
+      context: .
+      dockerfile: docker/Dockerfile.prod
+    container_name: game-api
+    depends_on:
+      - db
+    ports:
+      - "3000:3000"
+    env_file:
+      - .env
+    command: node dist/server.js
+
+volumes:
+  mongo_data:

src/problem5/backend-game-inventory/docker/Dockerfile.dev

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+FROM node:20
+
+WORKDIR /app
+
+COPY package*.json ./
+
+RUN npm install
+
+COPY . .
+
+EXPOSE 3000
+
+CMD ["npm", "run", "dev"]

src/problem5/backend-game-inventory/docker/Dockerfile.prod

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+# ===== BUILD STAGE =====
+FROM node:20 AS builder
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install
+
+COPY . .
+
+RUN npm run build
+
+
+# ===== RUNTIME STAGE =====
+FROM node:20
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install --omit=dev
+
+COPY --from=builder /app/dist ./dist
+
+COPY --from=builder /app/src/docs ./dist/docs
+
+EXPOSE 3000
+
+CMD ["node", "dist/server.js"]

src/problem5/backend-game-inventory/jest.config.js

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+const { createDefaultPreset } = require("ts-jest");
+
+const tsJestTransformCfg = createDefaultPreset().transform;
+
+/** @type {import("jest").Config} **/
+module.exports = {
+  testEnvironment: "node",
+  transform: {
+    ...tsJestTransformCfg,
+  },
+  preset: "ts-jest",
+  roots: ["<rootDir>/src"],
+  moduleFileExtensions: ["ts", "js"],
+  moduleNameMapper: {
+  "^@/(.*)$": "<rootDir>/src/$1"
+},
+  clearMocks: true
+};