A man from this country developed computers he broke codes to help his country win World War?

Answer 1

Many people from many countries helped with code breaking and the development of computers.

A notable example is Alan Turing from the UK though there were many others

This answer depends on your definition of computer. The Americans were working on the ENIAC computer to help with artillery calculations. This machine was not completed until after the war was over. The Brits were breaking the German codes with machines call bombes, but these were not true digital computers.

Early in WWII, the British captured a German code machine called the 'enigma'. They were able to do this without the Germans being aware of it. The Brits then figured out how it worked and were able to decode German military communications for most of the war. Early in this process they had to be careful not to do something that would make their code breaking obvious, so sometimes they had to 'ignore' information, but overall they did a great job of monitoring German communications.