A13303 | Ehab and Path-etic MEXs
时间限制1s
内存限制256MB
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题目描述
You are given a tree consisting of $n$ nodes. You want to write some labels on the tree's edges such that the following conditions hold:
- Every label is an integer between $0$ and $n-2$ inclusive.
- All the written labels are distinct.
- The largest value among $MEX(u,v)$ over all pairs of nodes $(u,v)$ is as small as possible.
Here, $MEX(u,v)$ denotes the smallest non-negative integer that isn't written on any edge on the unique simple path from node $u$ to node $v$ .
- Every label is an integer between $0$ and $n-2$ inclusive.
- All the written labels are distinct.
- The largest value among $MEX(u,v)$ over all pairs of nodes $(u,v)$ is as small as possible.
Here, $MEX(u,v)$ denotes the smallest non-negative integer that isn't written on any edge on the unique simple path from node $u$ to node $v$ .
输入格式
The first line contains the integer $n$ ( $2 \le n \le 10^5$ ) — the number of nodes in the tree.
Each of the next $n-1$ lines contains two space-separated integers $u$ and $v$ ( $1 \le u,v \le n$ ) that mean there's an edge between nodes $u$ and $v$ . It's guaranteed that the given graph is a tree.
Each of the next $n-1$ lines contains two space-separated integers $u$ and $v$ ( $1 \le u,v \le n$ ) that mean there's an edge between nodes $u$ and $v$ . It's guaranteed that the given graph is a tree.
输出格式
Output $n-1$ integers. The $i^{th}$ of them will be the number written on the $i^{th}$ edge (in the input order).
输入输出样例
输入 #1
3 1 2 1 3
输出 #1
0 1
输入 #2
6 1 2 1 3 2 4 2 5 5 6
输出 #2
0 3 2 4 1
The tree from the second sample:


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评测结果:Accepted