Deployed a Powerball smartcontract on XinFin XDC Network.

Deployed a powerball smartcontract on XinFin Network token by paying 0.0000007 usd transaction fees.

here my today's code:
pragma solidity ^0.4.18;
/// @title Powerball contract
contract Powerball {
struct Round {
uint endTime;
uint drawBlock;
uint[6] winningNumbers;
mapping(address => uint[6][]) tickets;
}
uint public constant TICKET_PRICE = 2e15;
uint public constant MAX_NUMBER = 69;
uint public constant MAX_POWERBALL_NUMBER = 26;
uint public constant ROUND_LENGTH = 3 days;
uint public round;
mapping(uint => Round) public rounds;
//constructor Powerball () public {
// round = 1;
// rounds[round].endTime = now + ROUND_LENGTH;
//}
function buy (uint[6][] numbers) payable public {
require(numbers.length * TICKET_PRICE == msg.value);
for (uint i=0; i < numbers.length; i++) {
for (uint j=0; j < 6; j++)
require(numbers[i][j] > 0);
for (j=0; j < 5; j++)
require(numbers[i][j] <= MAX_NUMBER);
require(numbers[i][5] <= MAX_POWERBALL_NUMBER);
}
// check for round expiry
if (now > rounds[round].endTime) {
rounds[round].drawBlock = block.number + 5;
round += 1;
rounds[round].endTime = now + ROUND_LENGTH;
}
for (i=0; i < numbers.length; i++)
rounds[round].tickets[msg.sender].push(numbers[i]);
}
function drawNumbers (uint _round) public {
uint drawBlock = rounds[_round].drawBlock;
require(now > rounds[_round].endTime);
require(block.number >= drawBlock);
require(rounds[_round].winningNumbers[0] == 0);
for (uint i=0; i < 5; i++) {
bytes32 rand = keccak256(block.blockhash(drawBlock), i);
uint numberDraw = uint(rand) % MAX_NUMBER + 1;
rounds[_round].winningNumbers[i] = numberDraw;
}
rand = keccak256(block.blockhash(drawBlock), uint(5));
uint powerballDraw = uint(rand) % MAX_POWERBALL_NUMBER + 1;
rounds[_round].winningNumbers[5] = powerballDraw;
}
function claim (uint _round) public {
require(rounds[_round].tickets[msg.sender].length > 0);
require(rounds[_round].winningNumbers[0] != 0);
uint[6][] storage myNumbers = rounds[_round].tickets[msg.sender];
uint[6] storage winningNumbers = rounds[_round].winningNumbers;
uint payout = 0;
for (uint i=0; i < myNumbers.length; i++) {
uint numberMatches = 0;
for (uint j=0; j < 5; j++) {
for (uint k=0; k < 5; k++) {
if (myNumbers[i][j] == winningNumbers[k])
numberMatches += 1;
}
}
bool powerballMatches = (myNumbers[i][5] == winningNumbers[5]);
// win conditions
if (numberMatches == 5 && powerballMatches) {
payout = this.balance;
break;
}
else if (numberMatches == 5)
payout += 1000 ether;
else if (numberMatches == 4 && powerballMatches)
payout += 50 ether;
else if (numberMatches == 4)
payout += 1e17; // .1 ether
else if (numberMatches == 3 && powerballMatches)
payout += 1e17; // .1 ether
else if (numberMatches == 3)
payout += 7e15; // .007 ether
else if (numberMatches == 2 && powerballMatches)
payout += 7e15; // .007 ether
else if (powerballMatches)
payout += 4e15; // .004 ether
}
msg.sender.transfer(payout);
delete rounds[_round].tickets[msg.sender];
}
function ticketsFor(uint _round, address user) public view
returns (uint[6][] tickets) {
return rounds[_round].tickets[user];
}
function winningNumbersFor(uint _round) public view
returns (uint[6] winningNumbers) {
return rounds[_round].winningNumbers;
}
}