My program is running in O(n) time (I hope so) but it is showing TLE in java. Can anyone please tell me what am I doing wrong here. I have used fast input with both BufferedWriter and PrintWriter but it is still showing tle. I know there is no problem with my logic because the same logic is accepted in C++. So can someone please tell me what is wrong with my java code.
Problem: 1324D - Pair of Topics
Edit 2: The code worked after I replaced array with ArrayList. Can anyone explain to me why did this happen? Thanks in advance.