A controller and a control method for internal combustion engine, and a memory medium are provided. A port injection ratio is changed according to an engine operating state of the internal combustion engine. The port injection ratio is a ratio of a port injection amount that is an amount of fuel injected by port injection valves to an amount of fuel supplied to cylinders from the port injection valves and direct injection valves. An injection reducing process causes a fuel injection amount in a reduced-injection cylinder to be smaller than a fuel injection amount in other cylinders. An increase limiting process limits increases in an adhered fuel amount in intake ports by regulating the port injection ratio during execution of the injection reducing process.