TPUSA (TPUSA)

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

/*
  TPUSA - Meme coin on Ethereum
  - ERC20-compatible (name, symbol, decimals, totalSupply, balanceOf, transfer, approve, transferFrom)
  - Burn function
  - Fixed supply: 69,000,000,000 TPUSA minted to deployer
  - No external imports; simple and gas-light
*/

contract TPUSA {
    string public name = "TPUSA";
    string public symbol = "TPUSA";
    uint8 public decimals = 18;

    uint256 public totalSupply = 69_000_000_000 * 1e18;

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    constructor() {
        balanceOf[msg.sender] = totalSupply;
        emit Transfer(address(0), msg.sender, totalSupply);
    }

    function transfer(address to, uint256 value) public returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function approve(address spender, uint256 value) public returns (bool) {
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        uint256 allowed = allowance[from][msg.sender];
        require(allowed >= value, "allowance");
        if (allowed != type(uint256).max) {
            allowance[from][msg.sender] = allowed - value;
        }
        _transfer(from, to, value);
        return true;
    }

    function burn(uint256 value) public returns (bool) {
        uint256 bal = balanceOf[msg.sender];
        require(bal >= value, "balance");
        unchecked {
            balanceOf[msg.sender] = bal - value;
            totalSupply -= value;
        }
        emit Transfer(msg.sender, address(0), value);
        return true;
    }

    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0), "zero");
        uint256 bal = balanceOf[from];
        require(bal >= value, "balance");
        unchecked {
            balanceOf[from] = bal - value;
            balanceOf[to] += value;
        }
        emit Transfer(from, to, value);
    }
}