YOU SAID:
I've came up with an idea
INTO JAPANESE
アイデアを思いつきました
BACK INTO ENGLISH
I came up with an idea.
INTO JAPANESE
アイデアを思いついた。
BACK INTO ENGLISH
I've got an idea!
INTO JAPANESE
アイデアを思いついた!
BACK INTO ENGLISH
I've got an idea!
Well done, yes, well done!