func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long N = 100100;   const long long Mod = 1e9 + 7;   long long Rec(long long i, long long j, long long c);   long long p[N];   long long x[N];   vector<long long> Adj[N];   vector<long long> Dp[N][2];   int main() {     long long n;     cin >> n;     for (long long i = 2; i <= n; i++)       scanf( %I64d , p + i), Adj[++p[i]].push_back(i);     for (long long i = 1; i <= n; i++) scanf( %I64d , x + i);     for (long long i = 0; i < N; i++)       Dp[i][0] = Dp[i][1] = vector<long long>(Adj[i].size(), -1);     cout << Rec(1, 0, 0);   }   long long Rec(long long i, long long j, long long c) {     if (j == 0) c += x[i];     if (c > 1) return 0;     if (j == Adj[i].size()) return c;     if (Dp[i][c][j] + 1) return Dp[i][c][j];     long long Res1 = (Rec(i, j + 1, c) * Rec(Adj[i][j], 0, 0)) % Mod;     long long Res2 = (c ? Rec(i, j + 1, 1) * Rec(Adj[i][j], 0, 1) : 0) % Mod;     long long Res3 = (!c ? (Rec(i, j + 1, 1) * Rec(Adj[i][j], 0, 0)) % Mod +                                (Rec(i, j + 1, 0) * Rec(Adj[i][j], 0, 1)) % Mod                          : 0) %                      Mod;     return Dp[i][c][j] = (Res1 + Res2 + Res3) % Mod;   }   