I can’t find the name/source at the moment, but if you enumerate all turing machines and run them concurrently* you will find the optimal algorithm for your problem in O(1) and executed that.
To my knowledge the algorithm is so inefficient on small input that it takes hours to solve integer addition.
You run the first turing machine one step, than the first two one additional step, that the first tree… This allows you to run an unlimited amount of TMs an unlimited amount of steps.