Answer:
The two major Allies' battle strategy for victory in Europe after December, 1941.
Leapfrogging Strategy :This strategy was used to block the attack from both sea and air, with the intention to separate/isolate Japaneses bases thus weakening their garrisons and reducing the Japan's ability to resupply and reinforce its forces
Island hopping strategy : It is a military strategy adopted by the allies against japan with the intention of taking over an island and developing a Military Base there.The occupied base was used as a launching point for the attackers and also to occupy other islands