Codeforces Round 245 (Div. 2)
C
Xor-tree
Codeforces
未评级
原题
← BD →
翻译中…

Iahub is very proud of his recent discovery, propagating trees. Right now, he invented a new tree, called xor-tree. After this new revolutionary discovery, he invented a game for kids which uses xor-trees.

翻译中…

The game is played on a tree having $*n*$ nodes, numbered from $1$ to $*n*$. Each node $*i*$ has an initial value $*init*_{*i*}$, which is either 0 or 1. The root of the tree is node 1.

翻译中…

One can perform several (possibly, zero) operations on the tree during the game. The only available type of operation is to pick a node $*x*$. Right after someone has picked node $*x*$, the value of node $*x*$ flips, the values of sons of $*x*$ remain the same, the values of sons of sons of $*x*$ flips, the values of sons of sons of sons of $*x*$ remain the same and so on.

翻译中…

The goal of the game is to get each node $*i*$ to have value $*goal*_{*i*}$, which can also be only 0 or 1. You need to reach the goal of the game by using minimum number of operations.

翻译中…

Input

翻译中…

The first line contains an integer $*n*$ ($1 ≤ *n* ≤ 10^{5}$). Each of the next $*n* - 1$ lines contains two integers $*u*_{*i*}$ and $*v*_{*i*}$ ($1 ≤ *u*_{*i*}, *v*_{*i*} ≤ *n*$; $*u*_{*i*} ≠ *v*_{*i*}$) meaning there is an edge between nodes $*u*_{*i*}$ and $*v*_{*i*}$.

翻译中…

The next line contains $*n*$ integer numbers, the $*i*$-th of them corresponds to $*init*_{*i*}$ ($*init*_{*i*}$ is either 0 or 1). The following line also contains $*n*$ integer numbers, the $*i*$-th number corresponds to $*goal*_{*i*}$ ($*goal*_{*i*}$ is either 0 or 1).

翻译中…

Output

翻译中…

In the first line output an integer number $*cnt*$, representing the minimal number of operations you perform. Each of the next $*cnt*$ lines should contain an integer $*x*_{*i*}$, representing that you pick a node $*x*_{*i*}$.

翻译中…

样例

Input #1
10
2 1
3 1
4 2
5 1
6 2
7 5
8 6
9 8
10 5
1 0 1 1 0 1 0 1 0 1
1 0 1 0 0 1 1 1 0 1
Output #1
2
4
7
InputCopy OutputCopy
题目信息
题号
430C
时间限制
1 s
内存限制
256 MB

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。