The problem is GSS1 and my solution is very close to AC but I just can't seem to find why my code gives SIGSEGV segmentation fault on G4G IDE. I request you to take a quick look at the code and let me know, it will be a big help! Thanks a lot!
PS- I used segment tree to store sum, maximum prefix sum, maximum suffix sum and maximum subarray sum in a segment.
Edit:- Nevermind, I found the mistake. I was initialising a node with all four variable values as LLONG_MIN which should't have been done because adding a negative number to that will cause overflow. Also, in build function I forgot the start>end case.