- Time limit: 1.00 s
- Memory limit: 512 MB
Given a tree of n nodes, your task is to count the number of distinct paths that consist of exactly k edges.
The first input line contains two integers n and k: the number of nodes and the path length. The nodes are numbered 1,2,\ldots,n.
Then there are n-1 lines describing the edges. Each line contains two integers a and b: there is an edge between nodes a and b.
Print one integer: the number of paths.
- 1 \le k \le n \le 2 \cdot 10^5
- 1 \le a,b \le n
5 2 1 2 2 3 3 4 3 5