With Strategy, the choice of algorithm is fairly stable. The State pattern allows an object to change its behavior when its internal state changes. This pattern can be observed in a vending machine. Vending machines have states based on the inventory, amount of currency deposited, the ability to make change, the item selected, etc. When currency is deposited and a selection is made, a vending machine will either deliver a product and no change, deliver a product and change, deliver no product due to insufficient currency on deposit, or deliver no product due to inventory depletion.
Flyweight explains when and how State objects can be shared.
Interpreter can use State to define parsing contexts. State is like Strategy except in its intent. Strategy has 2 different implementations, the first is similar to State. They differ in intent - that is, they solve different problems.