I attempted the D problem in JAVA 21 64bit with the simple logic of storing the remainder of a[i] in pairs along with their frequency in HashMap and check if (x-(a[i]%x)),(a[i]%y)) is already present, adding 1 to answer if it happens. I also make the remainder equal to x if it comes out to be zero.

Heres my solution

My Answer

but for some reason it fails the 12th test. I don't know what on God's Earth it is, but I then just convert the same logic to C++ and its accepted.

Where am I going wrong? What seems to be the problem here? Is there an alternative? A friend of mine suggested using a 2D array instead of a map an hence saving the trouble of creating pair class in JAVA but I could not fully grasp his concept. Please help me out here.