P24688 [AtCoder] Leaf Color
提高+
题目描述

Problem Statement

There is a tree T with N vertices numbered from 1 to N. The i-th edge connects vertices u_i and v_i. Additionally, vertex i is painted with color A_i.
Find the number, modulo 998244353, of (non-empty) subsets S of the vertex set of T that satisfy the following condition:

  • The induced subgraph G of T by S satisfies all of the following conditions:
  • G is a tree.
  • All vertices with degree 1 have the same color.

    What is an induced subgraph?

Let S be a subset of the vertices of a graph G. The induced subgraph of G by S is a graph whose vertex set is S and whose edge set consists of all edges in G that have both endpoints in S.

Input

The input is given from Standard Input in the following format:
N
$A_1 A_2 \dots A_N$
u_1 v_1
u_2 v_2
$\vdots$
u_{N-1} v_{N-1}

Output

Print the number, modulo 998244353, of (non-empty) subsets S of the vertex set of T that satisfy the condition in the problem statement.

Constraints

  • $1 \leq N \leq 2 \times 10^5$
  • $1 \leq A_i \leq N$
  • $1 \leq u_i \lt v_i \leq N$
  • The graph given in the input is a tree.
  • All input values are integers.

Sample Input 1

3
1 2 1
1 2
2 3

Sample Output 1

4

The following four sets of vertices satisfy the condition.

  • $\lbrace 1 \rbrace$
  • $\lbrace 1, 2, 3 \rbrace$
  • $\lbrace 2 \rbrace$
  • $\lbrace 3 \rbrace$

Sample Input 2

5
2 2 1 1 1
2 5
3 4
1 3
1 5

Sample Output 2

9

Sample Input 3

15
5 3 5 1 1 4 4 4 2 5 5 4 4 2 5
3 13
4 10
7 11
8 9
2 10
2 14
5 11
5 6
6 13
12 13
9 14
9 13
1 13
1 15

Sample Output 3

48

输入格式

见题面 Input 部分

输出格式

见题面 Output 部分

样例输入
3 1 2 1 1 2 2 3
样例输出
4