Problem is as follows ->
A tree is a connected graph that doesn't contain any cycles.
The distance between two vertices of a tree is the length (in edges) of the shortest path between these vertices.
You are given a tree with n vertices and a positive number k. Find the number of distinct pairs of the vertices which have a distance of exactly k between them. Note that pairs (v, u) and (u, v) are considered to be the same pair.
Constraints -> 1 ≤ n ≤ 50000, 1 ≤ k ≤ 500 , Edges 1 ≤ ai, bi ≤ n.
This is my submission -> 229435063
I think my time complexity is O(2*n*k), which is approximately 5*10^7 operations, which should work.
Any help would be appreciated :)
