Hello everybody,

Last year I read that dynamic trees exist, that is trees in which we create only the nodes we need since there can be a lot (say we have indices 1,...,10^9). I thought it's cool and wanted to know more about it. I googled a few times "Dynamic BIT", "Dynamic trees" or something like that but I found nothing...

Recently I participated in BOI 2015 and there was a problem that required a segment tree for 60 points and dynamic segment tree or AVL Tree which I can't code for full score so I wasn't able to get more than 60 on it. Now, I tried googling "Dynamic Segment Tree" but found nothing...

Can somebody please explain how dynamic segment trees work and give me an implementation, I would appreciate your help!

Thanks in advance! :)

UPD: Thanks everybody for the help, I understood it! So basically, we initially have the root only which stores the whole interval ([1;10^9] for example). Then the update/query goes exactly like in the normal segment tree but if we don't have a child of some node but we need it, we just create it and go on. I implemented Horrible Queries from SPOJ (I know that a normal segment tree is enough, but I wanted to test it). Here is my accepted code, it might be helpful for somebody who has problems with this structure — http://ideone.com/hdI5aX.