99techteam · tinhphandotco · Mar 16, 2026
diff --git a/src/problem1/test1.js b/src/problem1/test1.js
@@ -0,0 +1,25 @@
+var sum_to_n_a = function (n) {
+    //Time Complexity O(n)
+    let total = 0;
+    for (var i = 1; i <= n; i++) {
+        total += i;
+    }
+    return total;
+};
+
+var sum_to_n_b = function (n) {
+    //Time Complexity O(1)
+    return (n * (n + 1)) / 2;
+};
+
+var sum_to_n_c = function (n) {
+    //Time Complexity O(n)
+    let sum = 0;
+    let i = 1;
+    while (i <= n) {
+        sum += i;
+        i++;
+    }
+    return sum;
+};
+
diff --git a/src/problem2/index.html b/src/problem2/index.html
diff --git a/src/problem2/problem2/.gitignore b/src/problem2/problem2/.gitignore
@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
diff --git a/src/problem2/problem2/README.md b/src/problem2/problem2/README.md
@@ -0,0 +1,69 @@
+# React + TypeScript + Vite
+
+This template provides a minimal setup to get React working in Vite with HMR and some ESLint rules.
+
+Currently, two official plugins are available:
+
+- [@vitejs/plugin-react](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react) uses [Babel](https://babeljs.io/) for Fast Refresh
+- [@vitejs/plugin-react-swc](https://github.com/vitejs/vite-plugin-react/blob/main/packages/plugin-react-swc) uses [SWC](https://swc.rs/) for Fast Refresh
+
+## Expanding the ESLint configuration
+
+If you are developing a production application, we recommend updating the configuration to enable type-aware lint rules:
+
+```js
+export default tseslint.config([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      // Other configs...
+
+      // Remove tseslint.configs.recommended and replace with this
+      ...tseslint.configs.recommendedTypeChecked,
+      // Alternatively, use this for stricter rules
+      ...tseslint.configs.strictTypeChecked,
+      // Optionally, add this for stylistic rules
+      ...tseslint.configs.stylisticTypeChecked,
+
+      // Other configs...
+    ],
+    languageOptions: {
+      parserOptions: {
+        project: ['./tsconfig.node.json', './tsconfig.app.json'],
+        tsconfigRootDir: import.meta.dirname,
+      },
+      // other options...
+    },
+  },
+])
+```
+
+You can also install [eslint-plugin-react-x](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-x) and [eslint-plugin-react-dom](https://github.com/Rel1cx/eslint-react/tree/main/packages/plugins/eslint-plugin-react-dom) for React-specific lint rules:
+
+```js
+// eslint.config.js
+import reactX from 'eslint-plugin-react-x'
+import reactDom from 'eslint-plugin-react-dom'
+
+export default tseslint.config([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      // Other configs...
+      // Enable lint rules for React
+      reactX.configs['recommended-typescript'],
+      // Enable lint rules for React DOM
+      reactDom.configs.recommended,
+    ],
+    languageOptions: {
+      parserOptions: {
+        project: ['./tsconfig.node.json', './tsconfig.app.json'],
+        tsconfigRootDir: import.meta.dirname,
+      },
+      // other options...
+    },
+  },
+])
+```
diff --git a/src/problem2/problem2/eslint.config.js b/src/problem2/problem2/eslint.config.js
@@ -0,0 +1,23 @@
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+import tseslint from 'typescript-eslint'
+import { globalIgnores } from 'eslint/config'
+
+export default tseslint.config([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      js.configs.recommended,
+      tseslint.configs.recommended,
+      reactHooks.configs['recommended-latest'],
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+    },
+  },
+])
diff --git a/src/problem2/problem2/index.html b/src/problem2/problem2/index.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Currency swap</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>
diff --git a/src/problem2/problem2/package.json b/src/problem2/problem2/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "problem2",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "react": "^19.1.0",
+    "react-dom": "^19.1.0"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.30.1",
+    "@types/react": "^19.1.8",
+    "@types/react-dom": "^19.1.6",
+    "@vitejs/plugin-react": "^4.6.0",
+    "eslint": "^9.30.1",
+    "eslint-plugin-react-hooks": "^5.2.0",
+    "eslint-plugin-react-refresh": "^0.4.20",
+    "globals": "^16.3.0",
+    "typescript": "~5.8.3",
+    "typescript-eslint": "^8.35.1",
+    "vite": "^7.0.4"
+  }
+}
diff --git a/src/problem2/problem2/public/vite.svg b/src/problem2/problem2/public/vite.svg