ulong Recover(uint x0, uint x1, uint x2)
{
	Pcg32Single pcg = new(0);
	var stateField = pcg.GetType().GetField("_state", BindingFlags.NonPublic | BindingFlags.Instance);
	for (ulong upper = 0; upper < (1ul << 32); upper++)
	{
		var rot = (int) (upper >> 27);
		uint rotx0 = (x0 << rot) | (x0 >> (32 - rot));

		if (((rotx0 ^ upper >> 13) & ~31u) == (uint)(upper << 5))
		{
			uint high_lower_bits = (uint) ((rotx0 ^ upper >> 13) & 31u) << 27;
			for (uint lower = 0; lower < (1u << 27); lower++)
			{
				var candidate = (ulong)upper << 32 | high_lower_bits | lower;
				stateField.SetValue(pcg, candidate);

				if (pcg.GenerateNext() == x0 && pcg.GenerateNext() == x1 && pcg.GenerateNext() == x2)
					return candidate;
			}
		}
	}
	// Can't happen	
	throw new InvalidOperationException();
}

var random = new Random();
var seed = (ulong) random.NextInt64();
var pcg = new Pcg32Single(seed);

var x0 = pcg.GenerateNext();
var x1 = pcg.GenerateNext();
var x2 = pcg.GenerateNext();

Console.WriteLine(Recover(x0, x1, x2));