AtCoder Regular Contest 095
F
Permutation Tree
AtCoder
⌀ 2626
原题
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Problem Statement

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Takahashi has an ability to generate a tree using a permutation $(p_1,p_2,...,p_n)$ of $(1,2,...,n)$, in the following process:

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First, prepare Vertex $1$, Vertex $2$, ..., Vertex $N$. For each $i=1,2,...,n$, perform the following operation:

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  • If $p_i = 1$, do nothing.
  • If $p_i \neq 1$, let $j'$ be the largest $j$ such that $p_j < p_i$. Span an edge between Vertex $i$ and Vertex $j'$.
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Takahashi is trying to make his favorite tree with this ability. His favorite tree has $n$ vertices from Vertex $1$ through Vertex $n$, and its $i$-th edge connects Vertex $v_i$ and $w_i$. Determine if he can make a tree isomorphic to his favorite tree by using a proper permutation. If he can do so, find the lexicographically smallest such permutation.

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Note

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For the definition of isomorphism of trees, see wikipedia. Intuitively, two trees are isomorphic when they are the "same" if we disregard the indices of their vertices.

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Constraints

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  • $2 \leq n \leq 10^5$
  • $1 \leq v_i, w_i \leq n$
  • The given graph is a tree.
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Input

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Input is given from Standard Input in the following format:

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n
v_1 w_1
v_2 w_2
:
v_{n-1} w_{n-1}

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Output

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If there is no permutation that can generate a tree isomorphic to Takahashi's favorite tree, print -1. If it exists, print the lexicographically smallest such permutation, with spaces in between.

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样例

Input #1
6
1 2
1 3
1 4
1 5
5 6
Output #1
1 2 4 5 3 6
If the permutation $(1, 2, 4, 5, 3, 6)$ is used to generate a tree, it looks as follows: ![image](https://img.atcoder.jp/arc095/db000b879402aed649a1516620eb1e21.png) This is isomorphic to the given graph.
Input #2
6
1 2
2 3
3 4
1 5
5 6
Output #2
1 2 3 4 5 6
Input #3
15
1 2
1 3
2 4
2 5
3 6
3 7
4 8
4 9
5 10
5 11
6 12
6 13
7 14
7 15
Output #3
-1
题目信息
题号
arc095_d
时间限制
2 s
内存限制
256 MB

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