I don't know if it's just me, but the test cases for later problems are getting more annoying associated with minor issues of handling large numbers.

Anyway, I've got an solution for this problem. To arrive at the answer skipping the unneccessary intermediate steps, generate a list of all 's at the beginning (and this is where Python fails on the server without modulo, but not on my machine). It can be achieved easily if you observe the cases for odd and even separately.

After that, to get to the answer is just a matter of accumulating those 's. You are just one step away when you have the highest element of the answer.

Time out for all test cases in java. Time complexity of my solution is O(n) and space complexity is O(n). Any help ?

what will be value of b in this question pls

For n=20: 166116 249216 290766 311562 321960 327170 329775 331083 331737 332067 332232 332316 332358 332380 332391 332397 332400 332402 332403 332404

For n=100: 489471006, 479381980 ...

For n=10000: 673939922, 26088258 ...

For n=1000000: 459043758, 272140464 ...

Seems to time out -- is this doable in Python?