help in

my code :

my approach : i am taking 1 as the root and then calculate the nodes at every distance k (1 <= k <= 500) in it’s subtree and then for each node i am calculating the number of nodes at every distance k without considering it’s subtree. Finally i sum up all the values within the subtree and outside the subtree for the given k and as all the possible pairs are counted twice , i just make my answer half.

it is failing in test 21 please help me where i am going wrong !

please help me.

Hey dear. I tried debugging your code, yesterday and again today, with many small inputs but it returns the correct answer for all of them. Thats quite a bit over 40 TC.

I suspect that TC 21 is a really specific/special case where your approach is making some error in counting. Its really difficult (atleast for me) to come up with a corner case or find bug in the algo since whichever case I take, it seems to be working fine. Even that corner case, it works fine for N<=100. IDK perhaps the case is more than what I am seeing but yeah, it quite got me :frowning:

Your best bet is to look at one of the passed solution which resembles your approach and compare differences. That can help in coming up with corner case as well.