Neighbour Ordering

5000ms

262144K

Description:

Given an undirected graph $$$G$$$, we say that a neighbour ordering is an ordered list of all the neighbours of a vertex for each of the vertices of $$$G$$$. Consider a given neighbour ordering of $$$G$$$ and three vertices $$$u$$$, $$$v$$$ and $$$w$$$, such that $$$v$$$ is a neighbor of $$$u$$$ and $$$w$$$. We write $$$u <_{v} w$$$ if $$$u$$$ comes after $$$w$$$ in $$$v$$$'s neighbor list.

A neighbour ordering is said to be good if, for each simple cycle $$$v_1, v_2, \ldots, v_c$$$ of the graph, one of the following is satisfied:

$$$v_1 <_{v_2} v_3, v_2 <_{v_3} v_4, \ldots, v_{c-2} <_{v_{c-1}} v_c, v_{c-1} <_{v_c} v_1, v_c <_{v_1} v_2$$$.
$$$v_1 >_{v_2} v_3, v_2 >_{v_3} v_4, \ldots, v_{c-2} >_{v_{c-1}} v_c, v_{c-1} >_{v_c} v_1, v_c >_{v_1} v_2$$$.

Given a graph $$$G$$$, determine whether there exists a good neighbour ordering for it and construct one if it does.

Input:

The input consists of multiple test cases. The first line contains a single integer $$$t$$$ ($$$1 \leq t \leq 10^4$$$) — the number of test cases. Description of the test cases follows.

The first line of each test case contains two integers $$$n$$$ and $$$m$$$ ($$$2 \leq n \leq 3 \cdot 10^5$$$, $$$1 \leq m \leq 3 \cdot 10^5$$$), the number of vertices and the number of edges of the graph.

The next $$$m$$$ lines each contain two integers $$$u, v$$$ ($$$0 \leq u, v < n$$$), denoting that there is an edge connecting vertices $$$u$$$ and $$$v$$$. It is guaranteed that the graph is connected and there are no loops or multiple edges between the same vertices.

The sum of $$$n$$$ and the sum of $$$m$$$ for all test cases are at most $$$3 \cdot 10^5$$$.

Output:

For each test case, output one line with YES if there is a good neighbour ordering, otherwise output one line with NO. You can print each letter in any case (upper or lower).

If the answer is YES, additionally output $$$n$$$ lines describing a good neighbour ordering. In the $$$i$$$-th line, output the neighbours of vertex $$$i$$$ in order.

If there are multiple good neigbour orderings, print any.

Sample Input:

Sample Output:

Informação

Provedor Codeforces

Código CF1656I