Path with length k - MarisaOJ: Marisa Online Judge

Path with length k

Time limit: 1000 ms
Memory limit: 256 MB
Given a tree of $n$ vertices. Count the number of simple paths with length $k$. ### Input - The first line contains an integer $n$. - The next $n - 1$ lines, each line contains 2 integers $u, v$, there is an edge between $u$ and $v$. ### Output - Print the number of paths with length $k$. ### Constraints - $1 \le n \le 10^5$. - $1 \le k \le 100$. - $1 \le u, v \le n$. ### Example Input: ``` 5 2 1 2 2 3 1 4 4 5 ``` Output: ``` 3 ```