pragma solidity ^0.4.13;

contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) public constant returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender) public constant returns (uint256);
  function transferFrom(address from, address to, uint256 value) public returns (bool);
  function approve(address spender, uint256 value) public returns (bool);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract Ownable {
  address public owner;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  function Ownable() {
    owner = msg.sender;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  function transferOwnership(address newOwner) onlyOwner public {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }
}

library SaferMath {
  function mulX(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function divX(uint256 a, uint256 b) internal constant returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

  function sub(uint256 a, uint256 b) internal constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}

contract BasicToken is ERC20Basic {
  using SaferMath for uint256;
  mapping(address => uint256) balances;

  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  function balanceOf(address _owner) public constant returns (uint256 balance) {
    return balances[_owner];
  }

}

contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) allowed;

  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));

    uint256 _allowance = allowed[_from][msg.sender];

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = _allowance.sub(_value);
    Transfer(_from, _to, _value);
    return true;
  }

  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
    return allowed[_owner][_spender];
  }

  function increaseApproval (address _spender, uint _addedValue) returns (bool success) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  function decreaseApproval (address _spender, uint _subtractedValue) returns (bool success) {
    uint oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue > oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }
}

contract DEX is StandardToken, Ownable {

  string public constant name = "DEX Delta";
  string public constant symbol = "DEX";
  uint8 public constant decimals = 8;

  uint256 public constant SUPPLY_CAP = 99000000 * (10 ** uint256(decimals));

  address NULL_ADDRESS = address(0);


  event NoteChanged(string newNote);
  string public note = "DEX is official token of DEX Delta exchange";
  function setNote(string note_) public onlyOwner {
      note = note_;
      NoteChanged(note);
  }

  
  event PerformingDrop(uint count);
  function drop(address[] addresses, uint256 amount) public onlyOwner {
    uint256 amt = amount * 10**8;
    require(amt > 0);
    require(amt <= SUPPLY_CAP);
    PerformingDrop(addresses.length);
    
    // Maximum drop is 1000 addresses
    assert(addresses.length <= 1000);
    assert(balances[owner] >= amt * addresses.length);
    for (uint i = 0; i < addresses.length; i++) {
      address recipient = addresses[i];
      if(recipient != NULL_ADDRESS) {
        balances[owner] -= amt;
        balances[recipient] += amt;
        Transfer(owner, recipient, amt);
      }
    }
  }

  function DEX() {
    totalSupply = SUPPLY_CAP;
    balances[msg.sender] = SUPPLY_CAP;
  }
}