CF494D.Birthday

Ali is Hamed's little brother and tomorrow is his birthday. Hamed wants his brother to earn his gift so he gave him a hard programming problem and told him if he can successfully solve it, he'll get him a brand new laptop. Ali is not yet a very talented programmer like Hamed and although he usually doesn't cheat but this time is an exception. It's about a brand new laptop. So he decided to secretly seek help from you. Please solve this problem for Ali.

An $n$ -vertex weighted rooted tree is given. Vertex number $1$ is a root of the tree. We define $d(u,v)$ as the sum of edges weights on the shortest path between vertices $u$ and $v$ . Specifically we define $d(u,u)=0$ . Also let's define $S(v)$ for each vertex $v$ as a set containing all vertices $u$ such that $d(1,u)=d(1,v)+d(v,u)$ . Function $f(u,v)$ is then defined using the following formula:

The goal is to calculate $f(u,v)$ for each of the $q$ given pair of vertices. As the answer can be rather large it's enough to print it modulo $10^{9}+7$ .

Ali is Hamed's little brother and tomorrow is his birthday. Hamed wants his brother to earn his gift so he gave him a hard programming problem and told him if he can successfully solve it, he'll get him a brand new laptop. Ali is not yet a very talented programmer like Hamed and although he usually doesn't cheat but this time is an exception. It's about a brand new laptop. So he decided to secretly seek help from you. Please solve this problem for Ali.

An $n$ -vertex weighted rooted tree is given. Vertex number $1$ is a root of the tree. We define $d(u,v)$ as the sum of edges weights on the shortest path between vertices $u$ and $v$ . Specifically we define $d(u,u)=0$ . Also let's define $S(v)$ for each vertex $v$ as a set containing all vertices $u$ such that $d(1,u)=d(1,v)+d(v,u)$ . Function $f(u,v)$ is then defined using the following formula:

The goal is to calculate $f(u,v)$ for each of the $q$ given pair of vertices. As the answer can be rather large it's enough to print it modulo $10^{9}+7$ .

Ali is Hamed's little brother and tomorrow is his birthday. Hamed wants his brother to earn his gift so he gave him a hard programming problem and told him if he can successfully solve it, he'll get him a brand new laptop. Ali is not yet a very talented programmer like Hamed and although he usually doesn't cheat but this time is an exception. It's about a brand new laptop. So he decided to secretly seek help from you. Please solve this problem for Ali.

An $n$ -vertex weighted rooted tree is given. Vertex number $1$ is a root of the tree. We define $d(u,v)$ as the sum of edges weights on the shortest path between vertices $u$ and $v$ . Specifically we define $d(u,u)=0$ . Also let's define $S(v)$ for each vertex $v$ as a set containing all vertices $u$ such that $d(1,u)=d(1,v)+d(v,u)$ . Function $f(u,v)$ is then defined using the following formula:

The goal is to calculate $f(u,v)$ for each of the $q$ given pair of vertices. As the answer can be rather large it's enough to print it modulo $10^{9}+7$ .