题目描述
Problem Description
Given a rooted tree with $n$ nodes, where $1$ is the root, and $fa_u$ denotes the parent of node $u$. Additionally, a weight sequence $b$ of length $n$ is provided.
A permutation $a$ of length $n$ is considered a valid topological order for this tree if and only if $\forall 2 \le u \le n, a_u > a_{fa_u}$.
For each node $u$, define $f(u)$ as the sum of $b_{a_u}$ across all valid topological orders of the tree.
Now, for $1 \le u \le n$, compute $f(u) \bmod 10^9+7$.
Input Format
The first line contains an integer $n$, representing the number of nodes in the tree.
The second line contains $n-1$ integers, where the $i$-th integer denotes $fa_{i+1}$, describing the structure of the tree.
The third line contains $n$ integers, where the $i$-th integer denotes $b_i$, describing the weight sequence.
Output Format
A single line containing $n$ integers, where the $i$-th integer represents $f(i) \bmod 10^9+7$.
Sample Input and Output
Sample Input #1
5
1 1 3 2
3 5 4 4 1
Sample Output #1
18 27 27 15 15
Sample Input #2
5
1 1 3 1
1 2 3 4 5
Sample Output #2
12 42 32 52 42
Notes/Hints
| Subtask | $n \le$ | Special Constraints | Score |
|---|---|---|---|
| $1$ | $10$ | None | $5$ |
| $2$ | $20$ | None | $10$ |
| $3$ | $100$ | None | $15$ |
| $4$ | $350$ | None | $15$ |
| $5$ | $3000$ | A | $15$ |
| $6$ | $3000$ | None | $20$ |
| $7$ | $5000$ | None | $20$ |
Special Constraint A: $\forall 1 \le i \le n, b_i = i$.
For all data: $2 \le n \le 5000$, $1 \le fa_i < i$, $0 \le b_i < 10^9+7$.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分