Which kind of quantum circuits can be simulated with classical algorithms in a reasonable amount of time (for a large number of qubits)?
For example the ones with only Clifford gates. Or the ones with few non-local gates between the two halves of the circuit (via quasiprobability decomposition).
Are there any other examples of "constraints" that we can apply to a quantum circuit in order to be simulated faster than a standard classical simulation (i.e. it doesn't grow exponentially with the number of qubits)?