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ADAGRAFT - Ada and Graft |
As you might already know, Ada the Ladybug is a farmer. She grows a big fruit tree (with root in 0). There is a fruit on every node of the tree. Ada is competing in grafting competition and this is her masterpiece. The most valuable tree wins the competition. The value of tree is product of values of each node. The value of a node is the number of distinct fruit kinds in its subtree.
Can you find the value of Ada's tree? Since this number might be pretty big, output it modulo 109+7
Input
The first and line will contain 1 ≤ N ≤ 4*105.
The next line will contain N-1 integers 0 ≤ pi < i, the parent of ith node.
The next line will contain N integers 0 ≤ Fi ≤ 109, the fruit growing on ith node.
Output
Print a single integer - the value of tree modulo 1000000007.
Example Input
5 0 0 1 1 1 1 1 2 2
Example Output
4
Example Input
4 0 1 2 6 7 2 3
Example Output
24
Example Input
11 0 1 1 1 3 5 2 7 5 4 494052753 959648710 959648710 959648710 494052753 959648710 959648710 959648710 959648710 494052753 959648710
Example Output
32
Added by: | Morass |
Date: | 2017-11-06 |
Time limit: | 3s |
Source limit: | 50000B |
Memory limit: | 1536MB |
Cluster: | Cube (Intel G860) |
Languages: | All |
hide comments
2018-04-24 02:33:27
@julkas sorry,I personally think it is not a good habit to spoiler alert before solving the problem by themselves; |
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2018-03-31 08:31:49
In love with MO's <3 |
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2017-12-27 07:38:47 Shubhojeet Chakraborty
@julkas spoiler alert |
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2017-11-12 13:41:34
Good problem. Last edit: 2018-11-29 19:46:17 |