エイシングプログラミングコンテスト2021(AtCoder Beginner Contest 202)
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Problem Statement
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We have a rooted tree with $N$ vertices, numbered $1, 2, \dots, N$.
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Vertex $1$ is the root, and the parent of Vertex $i \, (2 \leq i \leq N)$ is Vertex $P_i$.
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You are given $Q$ queries. In the $i$-th query $(1 \leq i \leq Q)$, given integers $U_i$ and $D_i$, find the number of vertices $u$ that satisfy all of the following conditions:
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- Vertex
$U_i$is in the shortest path from$u$to the root (including the endpoints). - There are exactly
$D_i$edges in the shortest path from$u$to the root.
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Constraints
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$2 \leq N \leq 2 \times 10^5$$1 \leq P_i < i$$1 \leq Q \leq 2 \times 10^5$$1 \leq U_i \leq N$$0 \leq D_i \leq N - 1$- All values in input are integers.
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Input
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Input is given from Standard Input in the following format:
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N
P_2 P_3 \ldots P_N
Q
U_1 D_1
U_2 D_2
\vdots
U_Q D_Q
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Output
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Print $Q$ lines. The $i$-th line should contain the response to the $i$-th query.
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样例
Input #1
7
1 1 2 2 4 2
4
1 2
7 2
4 1
5 5
Output #1
3
1
0
0
In the $1$-st query, Vertices $4$, $5$, and $7$ satisfy the conditions. In the $2$-nd query, only Vertices $7$ satisfies the conditions. In the $3$-rd and $4$-th queries, no vertice satisfies the conditions.

题目信息
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