Codeforces Round 865 (Div. 1) |
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Finished |
You are given an undirected graph with $$$n$$$ vertices and $$$3m$$$ edges. The graph may contain multi-edges, but does not contain self-loops.
The graph satisfies the following property: the given edges can be divided into $$$m$$$ groups of $$$3$$$, such that each group is a triangle.
A triangle is defined as three edges $$$(a,b)$$$, $$$(b,c)$$$ and $$$(c,a)$$$ for some three distinct vertices $$$a,b,c$$$ ($$$1 \leq a,b,c \leq n$$$).
Initially, each vertex $$$v$$$ has a non-negative integer weight $$$a_v$$$. For every edge $$$(u,v)$$$ in the graph, you should perform the following operation exactly once:
After performing all operations, the following requirement should be satisfied: if $$$u$$$ and $$$v$$$ are connected by an edge, then $$$a_u \ne a_v$$$.
It can be proven this is always possible under the constraints of the task. Output a way to do so, by outputting the choice of $$$x$$$ for each edge. It is easy to see that the order of operations does not matter. If there are multiple valid answers, output any.
The first line contains a single integer $$$t$$$ ($$$1 \leq t \leq 10^5$$$) — the number of test cases. The description of test cases follows.
The first line of each test case contains two integers $$$n$$$ and $$$m$$$ ($$$3 \le n \le 10^6$$$, $$$1 \le m \le 4 \cdot 10^5$$$) — denoting the graph have $$$n$$$ vertices and $$$3m$$$ edges.
The second line of each test case contains $$$n$$$ integers $$$a_1,a_2,\ldots,a_n$$$ ($$$0 \leq a_i \leq 10^6$$$) — the initial weights of each vertex.
Then $$$m$$$ lines follow. The $$$i$$$-th line contains three integers $$$a_i$$$, $$$b_i$$$, $$$c_i$$$ ($$$1 \leq a_i < b_i < c_i \leq n$$$) — denotes that three edges $$$(a_i,b_i)$$$, $$$(b_i,c_i)$$$ and $$$(c_i,a_i)$$$.
Note that the graph may contain multi-edges: a pair $$$(x,y)$$$ may appear in multiple triangles.
It is guaranteed that the sum of $$$n$$$ over all test cases does not exceed $$$10^6$$$ and the sum of $$$m$$$ over all test cases does not exceed $$$4 \cdot 10^5$$$.
For each test case, output $$$m$$$ lines of $$$3$$$ integers each.
The $$$i$$$-th line should contains three integers $$$e_{ab},e_{bc},e_{ca}$$$ ($$$1 \leq e_{ab}, e_{bc} , e_{ca} \leq 4$$$), denoting the choice of value $$$x$$$ for edges $$$(a_i, b_i)$$$, $$$(b_i,c_i)$$$ and $$$(c_i, a_i)$$$ respectively.
44 10 0 0 01 2 35 20 0 0 0 01 2 31 4 54 43 4 5 61 2 31 2 41 3 42 3 45 40 1000000 412 412 4121 2 31 4 52 4 53 4 5
2 1 3 2 3 3 4 3 3 3 1 2 2 2 3 2 3 4 3 1 1 2 3 4 1 2 4 4 4 3 4 1 1
In the first test case, the initial weights are $$$[0,0,0,0]$$$. We have added values as follows:
The final weights are $$$[5,3,4,0]$$$. The output is valid because $$$a_1 \neq a_2$$$, $$$a_1 \neq a_3$$$, $$$a_2 \neq a_3$$$, and that all chosen values are between $$$1$$$ and $$$4$$$.
In the second test case, the initial weights are $$$[0,0,0,0,0]$$$. The weights after the operations are $$$[12,5,6,7,6]$$$. The output is valid because $$$a_1 \neq a_2$$$, $$$a_1 \neq a_3$$$, $$$a_2 \neq a_3$$$, and that $$$a_1 \neq a_4$$$, $$$a_1 \neq a_5$$$, $$$a_4 \neq a_5$$$, and that all chosen values are between $$$1$$$ and $$$4$$$.
In the third test case, the initial weights are $$$[3,4,5,6]$$$. The weights after the operations are $$$[19,16,17,20]$$$, and all final weights are distinct, which means no two adjacent vertices have the same weight.
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