[BOJ 12218] Symmetric Trees (Small)

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Points: 5
Time limit: 5.0s
Memory limit: 512M

Problem types
Allowed languages
Assembly, Awk, C, C++, Java, Pascal, Perl, Python, Sed, Text

Given a vertex-colored tree with N nodes, can it be drawn in a 2D plane with a line of symmetry?</p>

Formally, a tree is line-symmetric if each vertex can be assigned a location in the 2D plane such that:

  • All locations are distinct.
  • If vertex vi has color C and coordinates (xi, yi), there must also be a vertex vi' of color C located at (-xi, yi) -- Note if xi is 0, vi and vi' are the same vertex.
  • For each edge (vi, vj), there must also exist an edge (vi', vj').
  • If edges were represented by straight lines between their end vertices, no two edges would share any points except where adjacent edges touch at their endpoints.
## 입력 형식

The first line of the input gives the number of test cases, T. T test cases follow.

Each test case starts with a line containing a single integer N, the number of vertices in the tree.

N lines then follow, each containing a single uppercase letter. The i-th line represents the color of the i-th node.

N-1 lines then follow, each line containing two integers i and j (1 ≤ i < jN). This denotes that the tree has an edge from the i-th vertex to the j-th vertex. The edges will describe a connected tree.

Limits

  • 1 ≤ T ≤ 100.
  • 2 ≤ N ≤ 12.
## 출력 형식

For each test case, output one line containing "Case #x: y", where x is the case number (starting from 1) and y is "SYMMETRIC" if the tree is line-symmetric by the definition above or "NOT SYMMETRIC" if it isn't.

예제 입력

3
4
R
G
B
B
1 2
2 3
2 4
4
R
G
B
Y
1 2
2 3
2 4
12
Y
B
Y
G
R
G
Y
Y
B
B
B
R
1 3
1 9
1 10
2 3
3 7
3 8
3 11
4 8
5 7
6 7
8 12

예제 출력

Case #1: SYMMETRIC
Case #2: NOT SYMMETRIC
Case #3: SYMMETRIC

힌트

The first case can be drawn as follows:</p>

No arrangement of the second case has a line of symmetry:

One way of drawing the third case with a symmetry line is as follows:


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