✨ Complete Base Learn Solutions - All 13 Exercises

Battle-tested smart contracts for earning all Base Learn NFTs!

Features:
- 13 working smart contract solutions
- Verified on Base Sepolia testnet
- Clean, documented code
- Easy deployment scripts
- Comprehensive README

Successfully earns:
- 13 Soulbound NFTs
- Guild.xyz roles (Newcomer → Supreme)
- 13 TalentProtocol points

Ready to deploy and earn your NFTs! 🚀

Author: JSONbored

.env.example

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+# Private key for deploying contracts (DO NOT COMMIT REAL KEYS!)
+PRIVATE_KEY=your_private_key_here
+
+# RPC URLs
+BASE_SEPOLIA_RPC=https://sepolia.base.org
+SEPOLIA_RPC=https://rpc.sepolia.org
+
+# API Keys for contract verification
+BASESCAN_API_KEY=your_basescan_api_key
+ETHERSCAN_API_KEY=your_etherscan_api_key
+
+# Gas reporting (optional)
+REPORT_GAS=false
+COINMARKETCAP_API_KEY=your_coinmarketcap_api_key
+
+# Base Learn Platform credentials (if needed)
+BASE_LEARN_WALLET=your_wallet_address

.gitignore

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+# Dependencies
+node_modules/
+.pnp
+.pnp.js
+
+# Testing
+coverage/
+coverage.json
+
+# Production
+build/
+dist/
+
+# Hardhat
+artifacts/
+cache/
+typechain-types/
+
+# Environment variables
+.env
+.env.local
+.env.development.local
+.env.test.local
+.env.production.local
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.DS_Store
+
+# Logs
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Deployments (keep structure but not addresses)
+deployments/*/*
+!deployments/*/
+
+# Misc
+.openzeppelin/
+.defender/
+*.log
+temp/
+tmp/

README.md

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+# Base Learn Solutions 🎓
+
+Complete, working smart contract solutions for all 13 Base Learn exercises. Earn your NFTs and unlock Guild.xyz roles! 🏆
+
+## 🚀 Overview
+
+This repository contains battle-tested smart contracts that successfully pass all Base Learn validations. Each contract has been deployed and verified to mint the corresponding NFT on Base Sepolia testnet.
+
+### What you'll earn:
+- ✅ **13 Soulbound NFTs** - Proof of your smart contract mastery
+- 🏅 **Guild.xyz Roles** - Newcomer, Acolyte, Consul, Prefect, Supreme
+- 💎 **13 TalentProtocol Points** - Build your on-chain reputation
+
+## 📋 Prerequisites
+
+- Node.js v18+ and npm
+- MetaMask or Coinbase Wallet
+- Base Sepolia ETH (get from [faucet](https://www.coinbase.com/faucets/base-ethereum-goerli-faucet))
+- Basic understanding of Solidity and smart contracts
+
+## 🛠 Installation
+
+```bash
+# Clone the repository
+git clone https://github.com/YOUR_USERNAME/base-learn-solutions.git
+cd base-learn-solutions
+
+# Install dependencies
+npm install
+
+# Set up environment variables
+cp .env.example .env
+# Edit .env and add your private key (NEVER commit this!)
+```
+
+## 📁 Contract Solutions
+
+Each exercise is in its own directory with the exact contract name Base Learn expects:
+
+| Exercise | Contract | Description |
+|----------|----------|-------------|
+| 01 | `BasicMath.sol` | Overflow-safe arithmetic operations |
+| 02 | `ControlStructures.sol` | FizzBuzz and time-based logic |
+| 03 | `EmployeeStorage.sol` | Optimized storage patterns |
+| 04 | `FavoriteRecords.sol` | Array manipulation |
+| 05 | `FavoriteRecords.sol` | Mapping operations |
+| 06 | `InheritanceContracts.sol` | Contract inheritance patterns |
+| 07 | `GarageManager.sol` | Struct management |
+| 08 | `ErrorTriageExercise.sol` | Error handling and debugging |
+| 09 | `AddressBookFactory.sol` | Factory pattern with `new` keyword |
+| 10 | `ImportsExercise.sol` | Library imports and usage |
+| 11 | `HaikuNFT.sol` | ERC-721 NFT implementation |
+| 12 | `UnburnableToken.sol` | Minimal token implementation |
+| 13 | `WeightedVoting.sol` | ERC-20 governance token |
+
+## 🚀 Deployment Guide
+
+### Deploy All Contracts
+
+```bash
+# Compile all contracts
+npx hardhat compile
+
+# Deploy to Base Sepolia
+npx hardhat run scripts/deploy-all.ts --network baseSepolia
+```
+
+### Deploy Individual Contracts
+
+```bash
+# Deploy specific exercise (replace XX with exercise number)
+npx hardhat run scripts/deploy-XX.ts --network baseSepolia
+```
+
+## ✅ Submission Process
+
+1. **Deploy your contracts** to Base Sepolia testnet
+2. **Copy the deployed contract address** from the terminal
+3. **Visit [Base Learn](https://docs.base.org/base-learn/docs/welcome)** 
+4. **Navigate to the exercise** you want to submit
+5. **Paste your contract address** and click submit
+6. **Mint your NFT** after successful validation
+
+## 🔑 Important Notes
+
+### Security
+- **NEVER** commit your `.env` file or private keys
+- Use a dedicated wallet for testnet deployments
+- Keep your private keys secure
+
+### Validation Tips
+- Base Learn expects **exact** function signatures
+- Don't modify function names or parameters
+- Some exercises require specific Solidity versions
+- If validation fails, check gas estimation errors
+
+### Common Issues
+- **"Unable to estimate network fee"** - Contract validation failed
+- **"Transaction underpriced"** - Wait for pending transactions to clear
+- **Validation failures** - Ensure exact function signatures match
+
+## 📚 Resources
+
+- [Base Learn Platform](https://docs.base.org/base-learn/docs/welcome)
+- [Base Documentation](https://docs.base.org/)
+- [Base Sepolia Faucet](https://www.coinbase.com/faucets/base-ethereum-goerli-faucet)
+- [Base Sepolia Explorer](https://sepolia.basescan.org)
+- [Guild.xyz Base Learn](https://guild.xyz/base-learn)
+
+## 🤝 Contributing
+
+Found an issue or have an improvement? Contributions are welcome!
+
+1. Fork the repository
+2. Create your feature branch (`git checkout -b feature/improvement`)
+3. Commit your changes (`git commit -m 'Add improvement'`)
+4. Push to the branch (`git push origin feature/improvement`)
+5. Open a Pull Request
+
+## 📜 License
+
+MIT License - feel free to use these solutions to complete Base Learn!
+
+## 🙏 Acknowledgments
+
+- Base Learn team for creating this educational platform
+- OpenZeppelin for secure contract libraries
+- The Base ecosystem community
+
+---
+
+**⚡ Ready to become a Base Learn graduate?** Deploy these contracts and earn your NFTs!
+
+Remember: Learning by doing is the best way to master smart contracts. Use these solutions to understand the patterns, then try building your own variations! 🚀

contracts/01-BasicMath/BasicMath.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+contract BasicMath {
+    function adder(uint256 _a, uint256 _b) external pure returns (uint256 sum, bool error) {
+        unchecked {
+            sum = _a + _b;
+            if (sum < _a || sum < _b) {
+                return (0, true);
+            }
+            return (sum, false);
+        }
+    }
+
+    function subtractor(uint256 _a, uint256 _b) external pure returns (uint256 difference, bool error) {
+        if (_b > _a) {
+            return (0, true);
+        }
+        return (_a - _b, false);
+    }
+}

contracts/02-ControlStructures/ControlStructures.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+contract ControlStructures {
+    error AfterHours(uint256 time);
+
+    function fizzBuzz(uint256 _number) public pure returns (string memory response) {
+        if (_number % 3 == 0 && _number % 5 == 0) {
+            return "FizzBuzz";
+        } else if (_number % 3 == 0) {
+            return "Fizz";
+        } else if (_number % 5 == 0) {
+            return "Buzz";
+        } else {
+            return "Splat";
+        }
+    }
+
+    function doNotDisturb(uint256 _time) public pure returns (string memory result) {
+        assert(_time < 2400);
+        
+        if (_time > 2200 || _time < 800) {
+            revert AfterHours(_time);
+        } else if (_time >= 1200 && _time <= 1299) {
+            revert("At lunch!");
+        } else if (_time >= 800 && _time <= 1199) {
+            return "Morning!";
+        } else if (_time >= 1300 && _time <= 1799) {
+            return "Afternoon!";
+        } else if (_time >= 1800 && _time <= 2200) {
+            return "Evening!";
+        }
+    }
+}

contracts/03-Storage/EmployeeStorage.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+contract EmployeeStorage {
+    uint16 private shares;
+    uint32 private salary;
+    uint256 public idNumber;
+    string public name;
+
+    constructor(uint16 _shares, string memory _name, uint32 _salary, uint _idNumber) {
+        shares = _shares;
+        name = _name;
+        salary = _salary;
+        idNumber = _idNumber;
+    }
+
+    function viewShares() public view returns (uint16) {
+        return shares;
+    }
+
+    function viewSalary() public view returns (uint32) {
+        return salary;
+    }
+
+    error TooManyShares(uint16 _shares);
+
+    function grantShares(uint16 _newShares) public {
+        if (_newShares > 5000) {
+            revert("Too many shares");
+        } else if (shares + _newShares > 5000) {
+            revert TooManyShares(shares + _newShares);
+        }
+        shares += _newShares;
+    }
+
+    function checkForPacking(uint _slot) public view returns (uint r) {
+        assembly {
+            r := sload (_slot)
+        }
+    }
+
+    function debugResetShares() public {
+        shares = 1000;
+    }
+}

contracts/04-Arrays/FavoriteRecords.sol

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+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.17;
+
+contract FavoriteRecords {
+    mapping(string => bool) private approvedRecords;
+    string[] private approvedRecordsIndex;
+    
+    mapping(address => mapping(string => bool)) public userFavorites;
+    mapping(address => string[]) private userFavoritesIndex;
+
+    error NotApproved(string albumName);
+
+    constructor() {
+        approvedRecordsIndex = [
+            "Thriller",
+            "Back in Black",
+            "The Bodyguard",
+            "The Dark Side of the Moon",
+            "Their Greatest Hits (1971-1975)",
+            "Hotel California",
+            "Come On Over",
+            "Rumours",
+            "Saturday Night Fever"
+        ];
+        
+        for (uint i = 0; i < approvedRecordsIndex.length; i++) {
+            approvedRecords[approvedRecordsIndex[i]] = true;
+        }
+    }
+
+    function getApprovedRecords() public view returns (string[] memory) {
+        return approvedRecordsIndex;
+    }
+
+    function addRecord(string memory _albumName) public {
+        if (!approvedRecords[_albumName]) {
+            revert NotApproved({albumName: _albumName});
+        }
+        
+        if (!userFavorites[msg.sender][_albumName]) {
+            userFavorites[msg.sender][_albumName] = true;
+            userFavoritesIndex[msg.sender].push(_albumName);
+        }
+    }
+
+    function getUserFavorites(address _address) public view returns (string[] memory) {
+        return userFavoritesIndex[_address];
+    }
+
+    function resetUserFavorites() public {
+        for (uint i = 0; i < userFavoritesIndex[msg.sender].length; i++) {
+            string memory albumName = userFavoritesIndex[msg.sender][i];
+            userFavorites[msg.sender][albumName] = false;
+        }
+        delete userFavoritesIndex[msg.sender];
+    }
+}