MazeHashFunction.sol

contract MazeHashFunction {
        
    function generateRandomNumber(uint _treasureMap) view public returns (uint) {
        
        bytes memory randomNumber = new bytes(32);
        bytes memory treasureMapInBytes = toBytes(_treasureMap);
        uint8 nextByteInTreasureMap = uint8(treasureMapInBytes[31]);
        uint8 pointerToNextPosition = nextByteInTreasureMap;
        for(uint i = 31; i >0; i--) {
            uint nextHashInLabyrinth = uint(blockhash(block.number - 1 - pointerToNextPosition));
            bytes memory blockHashToBytes = toBytes(nextHashInLabyrinth);
            uint8 byteFromBlockhash = uint8(blockHashToBytes[i]);
            nextByteInTreasureMap = uint8(treasureMapInBytes[i]);
            uint8 nextRandomNumber = nextByteInTreasureMap ^ byteFromBlockhash;
            randomNumber[i] = bytes1(nextRandomNumber);
            pointerToNextPosition = nextRandomNumber;
        }
        return toUint(randomNumber);
    }
    function toBytes(uint256 x) pure internal returns (bytes b) {
        b = new bytes(32);
        assembly { mstore(add(b, 32), x) }
    }
    function toUint(bytes x) pure internal returns (uint b) {
        assembly {
            b := mload(add(x, 0x20))
        }
    }
}