题目描述
Problem Statement
Given is an undirected graph with N vertices and M edges. The i-th edge connects Vertices A_i and B_i and has a weight of C_i.
Initially, all vertices are painted black. You can do the following operation at most K times.
- Operation: choose any vertex v and any integer x. Paint red all vertices reachable from the vertex v by traversing edges whose weights are at most x, including v itself.
How many sets can be the set of vertices painted red after the operations?
Find the count modulo 998244353.
Input
Input is given from Standard Input in the following format:
N M K
A_1 B_1 C_1
$\vdots$
A_M B_M C_M
Output
Print the answer.
Constraints
- $2 \leq N \leq 10^5$
- $0 \leq M \leq 10^5$
- $1 \leq K \leq 500$
- $1 \leq A_i,B_i \leq N$
- $1 \leq C_i \leq 10^9$
- All values in input are integers.
Sample Input 1
3 2 1
1 2 1
2 3 2
Sample Output 1
6
For example, an operation with (v,x)=(2,1) paints Vertices 1,2 red, and an operation with (v,x)=(1,0) paints Vertex 1.
After at most one operation, the set of vertices painted red can be one of the following six: {},{1},{2},{3},{1,2},{1,2,3}.
Sample Input 2
5 0 2
Sample Output 2
16
The given graph may not be connected.
Sample Input 3
6 8 2
1 2 1
2 3 2
3 4 3
4 5 1
5 6 2
6 1 3
1 2 10
1 1 100
Sample Output 3
40
The given graph may have multi-edges and self-loops.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分