I’ve AC, but I still have a question!

My first program used “unsigned long” type, and didn’t pass Test 12

Then I changed all types to “unsigned long long” , and program was AC.

So, my question is why my first program failed on Test12?

As you know n,m<=2^31-1;So, the biggest result is 0xFFFFFFFD! This result can be represented by unsigned long!

So, I didn’t announce my program, because it is bad style. I’m sure that those programmers who solved this issue can understand my question….

Best Wishes,
Veniamin.

Each of n and m is <= 2^31-1. Yes, they are unsigned long.

But max unsigned long + 1 is? Overflow, of course !!

Your solution doesn't print n or m exactly but you have to calculate either 2*m or 2*n, aren't you?

Thanks.I also meet this question.