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random

contract random{
    function rand(uint min, uint max) public returns (bytes32){
        uint256 lastBlockNumber = block.number - 1;
        bytes32 hashVal = bytes32(block.blockhash(lastBlockNumber));
        return bytes32(hashVal);
}
}

random2

contract random{
    function rand(uint min, uint max) public returns (uint256){
        
        uint256 lastBlockNumber = block.number - 1;
        uint256 hashVal = uint256(block.blockhash(lastBlockNumber));
        
        
        // This turns the input data into a 100-sided die
        // by dividing by ceil(2 ^ 256 / 100).
        uint256 FACTOR = 1157920892373161954235709850086879078532699846656405640394575840079131296399;
        return uint256(uint256(hashVal) / FACTOR) + 1;
}
}