RandomWithSeedString

public void Test(string seed)
{
    var seedNum = 0;
    foreach (var c in seed)
    {
        seedNum += (int)c;
    }
    return new System.Random(seedNum);
}

RandomWithSeedStringAndNumber

public void Test(string seed, int floor)
{
    long randomSeed = 0;
    foreach (var c in seed)
    {
        randomSeed = (randomSeed + (int)c) * ((int)c + floor) % Int32.MaxValue;
    }
    
    var random = new System.Random((int)randomSeed);
    random.Next(100)
}