CSU1660: K-Cycle

CSU1660: K-Cycle
Description

A simple cycle is a closed simple path, with no other repeated vertices or edges other than the starting and ending vertices. the length of a cycle is the number of vertices on it. given an undirected graph G (V, E), you are to detect whether it contains a simple cycle of length K. to make the problem easier, we only consider cases with small K here.

Input

There are multiple test cases.
The first line will contain in a positive integer T (T ≤ 10) meaning the number of test cases.
For each test case, the first line contains three positive integers N, M and K (N ≤ 50, M ≤ 500, 3 ≤ K ≤ 7 ). N is the number of vertices of the graph, M is the number of edges and K is the length of the cycle desired. next follow M lines, each line contains two integers A and B, describing an undirected edge AB of the graph. vertices are numbered from 0 to N-1.

Output

For each test case, you shocould output "YES" in one line if there is a cycle of length K in the given graph, otherwise output "NO ".

Sample Input

26 8 40 11 22 03 44 55 31 32 44 4 30 11 22 33 0

Sample Output

YESNO

HINT

 

Source
Q: Can I find a k-length ring in a graph?
Idea: directly search for repeated access points

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