【算法代码】

#include <bits/stdc++.h>
using namespace std;

const int maxn=1e5+5;
vector<int> v[maxn];
int cnt[maxn]; //times that a node has been operated

void dfs(int x,int num) {
    for(int i=0; i<v[x].size(); i++) {
        int j=v[x][i];
        cnt[j]+=num;;
        dfs(j,cnt[j]);
    }
}

int main() {
    int n,idx;
    cin>>n;
    for(int i=2; i<=n; i++) {
        cin>>idx;
        v[idx].push_back(i);
    }

    string s;
    int q;
    cin>>s>>q;
    while(q--) {
        int x;
        cin>>x;
        cnt[x]++;
    }

    dfs(1,cnt[1]);
    for(int i=1; i<=n; i++) { //Even is white, odd is black.
        if(cnt[i]%2==0) s[i-1]=='1'?cout<<1:cout<<0;
        else s[i-1]=='1'?cout<<0:cout<<1;
    }

    return 0;
}

/*
in:
6
3 1 1 3 4
100101
3
1
3
2

out:
010000
*/