codeforces 429A（dfs）

#include<bits/stdc++.h>
#define x first
#define y second
#define IOS ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
typedef unsigned long long ULL;
typedef pair<int,int> PII;
typedef pair<long,long> PLL;
typedef pair<char,char> PCC;
typedef long long LL;
const int N=3*1e5+10;
const int M=150;
const int INF=0x3f3f3f3f;
const int MOD=998244353;
int n,init[N],goal[N];
vector<int> g[N];
vector<int> ans;
void dfs(int node,int father,int state,int odd,int even){
    if((state && odd) || (!state && even)) init[node]^=1;

    if(init[node]!=goal[node]){
        ans.push_back(node);
        if(state) odd^=1;
        else even^=1;
    }

    for(int i=0;i<g[node].size();i++){
        if(g[node][i]==father) continue;
        dfs(g[node][i],node,(state+1)%2,odd,even);
    }
}
void solve(){
    cin>>n;
    for(int i=0;i<n-1;i++){
        int x,y;cin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for(int i=1;i<=n;i++) cin>>init[i];
    for(int i=1;i<=n;i++) cin>>goal[i];
    dfs(1,-1,1,0,0);
    cout<<ans.size()<<endl;
    for(int i=0;i<ans.size();i++) cout<<ans[i]<<endl;
}
int main(){
    IOS;
    solve();
    return 0;
}