99techteam · daocuong11 · Jan 25, 2026
diff --git a/src/problem1/solution.js b/src/problem1/solution.js
@@ -0,0 +1,32 @@
+// Problem 1: Three ways to sum to n
+
+// Method 1: Using a for loop (iterative approach)
+var sum_to_n_a = function(n) {
+    let sum = 0;
+    for (let i = 1; i <= n; i++) {
+        sum += i;
+    }
+    return sum;
+};
+
+// Method 2: Using the mathematical formula n * (n + 1) / 2
+var sum_to_n_b = function(n) {
+    return (n * (n + 1)) / 2;
+};
+
+// Method 3: Using recursion
+var sum_to_n_c = function(n) {
+    if (n <= 1) {
+        return n;
+    }
+    return n + sum_to_n_c(n - 1);
+};
+
+// Test cases
+console.log('Testing sum_to_n_a(5):', sum_to_n_a(5)); // Expected: 15
+console.log('Testing sum_to_n_b(5):', sum_to_n_b(5)); // Expected: 15
+console.log('Testing sum_to_n_c(5):', sum_to_n_c(5)); // Expected: 15
+
+console.log('\nTesting sum_to_n_a(10):', sum_to_n_a(10)); // Expected: 55
+console.log('Testing sum_to_n_b(10):', sum_to_n_b(10)); // Expected: 55
+console.log('Testing sum_to_n_c(10):', sum_to_n_c(10)); // Expected: 55
diff --git a/src/problem2/README.md b/src/problem2/README.md
@@ -0,0 +1,81 @@
+# Currency Swap Form - React + Vite
+
+A modern, interactive currency swap form built with React and Vite.
+
+## Features
+
+- ⚛️ **React 18** - Modern React with hooks
+- ⚡ **Vite** - Lightning-fast HMR and optimized builds
+- 💱 **Real-time conversion** - Live currency exchange rate calculations
+- 🔄 **Bidirectional editing** - Edit either send or receive amount
+- ✨ **Smooth animations** - Professional UI with smooth transitions
+- ✅ **Input validation** - Real-time error messages and validation
+- 📱 **Responsive design** - Works seamlessly on all device sizes
+- 🎨 **Modern UI** - Beautiful gradient theme with intuitive interactions
+
+## Getting Started
+
+### Installation
+
+```bash
+npm install
+```
+
+### Development
+
+Start the development server with hot module replacement:
+
+```bash
+npm run dev
+```
+
+The app will open automatically at `http://localhost:3000`
+
+### Build
+
+Create an optimized production build:
+
+```bash
+npm run build
+```
+
+### Preview
+
+Preview the production build locally:
+
+```bash
+npm run preview
+```
+
+## Project Structure
+
+```
+problem2/
+├── src/
+│   ├── components/
+│   │   ├── CurrencySwap.jsx    # Main currency swap component
+│   │   └── CurrencySwap.css    # Component styles
+│   ├── App.jsx                 # Root component
+│   ├── App.css                 # App-level styles
+│   └── main.jsx                # Application entry point
+├── index.html                  # HTML template
+├── vite.config.js              # Vite configuration
+└── package.json                # Project dependencies
+```
+
+## Technologies
+
+- **React 18** - UI library with hooks
+- **Vite** - Next generation frontend tooling
+- **CSS3** - Animations and responsive design
+
+## Supported Currencies
+
+- USD - US Dollar
+- EUR - Euro
+- GBP - British Pound
+- JPY - Japanese Yen
+- AUD - Australian Dollar
+- CAD - Canadian Dollar
+- CHF - Swiss Franc
+- CNY - Chinese Yuan
diff --git a/src/problem2/index.html b/src/problem2/index.html
@@ -1,27 +1,12 @@
-<html>
-
-<head>
-  <meta name="viewport" content="width=device-width, initial-scale=1">
-  <title>Fancy Form</title>
-
-  <!-- You may add more stuff here -->
-  <link href="style.css" rel="stylesheet" />
-</head>
-
-<body>
-
-  <!-- You may reorganise the whole HTML, as long as your form achieves the same effect. -->
-  <form onsubmit="return !1">
-    <h5>Swap</h5>
-    <label for="input-amount">Amount to send</label>
-    <input id="input-amount" />
-
-    <label for="output-amount">Amount to receive</label>
-    <input id="output-amount" />
-
-    <button>CONFIRM SWAP</button>
-  </form>
-  <script src="script.js"></script>
-</body>
-
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Currency Swap - React + Vite</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.jsx"></script>
+  </body>
 </html>