I just want to discuss and solve to problems on SJTUOJ with others.(start with 4001)
Because I am lazy~_(:з」∠) , So update is unscheduled ~

Update 10 problem each time (Accepted or unsolved).
In this .md, I will show the number of these ten questions and unsolved problems' link.

Please solve the problems which is unsolved in these 10 problems.
Please do not advance._(:з」∠)
You can also update your better algorithm in all accepted problems.

Java is preferable, and C,C++,Python is OK
(I will change them to Java in the end, because Java is the best programming language in the world(,,・ω・,,))
beg for note in your code.╥﹏╥

focus on 4001 - 4010 recently.
and 4005,4007,4009,4010 are unsolved