What an awful description. It simply doesnt tell the case swapping rules in the top part. Also you could shorten the description by half at least.
You could narrow it down to: "Each character case in string A should be changed N times, where N is the number of times the same character occured in the string B, regardless of its case."

Fixed, thanks.

there's mistake in description --> "di" = 4

c00l

Great kata, awesome description, thanks! :)

Thanks

the only guy having fun here :) tried similar stuff, but gave up...

fixed + upgraded to JUnit 5

great kata, thanks! learned something new :)

great kata, worst description ever though

little hard, but very very good kata, thanks!

description probably should specify there will be only integer numbers in test cases

first top voted solution that is really cool in a while