func_code_string:     #include <bits/stdc++.h>       using namespace std;               #define endl   n        #define ll long long       #define INF (ll)1e18               ll i, i1, j, k, k1, t, n, m, res, check1, a[200010], a1, b, d, v, dist[200010], dp[200010], s, s1, s2;       vector<ll> adj[200010];       vector<array<ll, 3>> dadj[200010];       bool visited[200010];               void dfs(ll s) {           for (auto u : adj[s]) {               if (!visited[u]) {                   visited[u] = true;                   dist[u] = dist[s] + 1;                   dadj[dist[u]].push_back({-1, s, u});                   d = max(d, dist[u]);                   dfs(u);               }           }       }               int main() {           ios::sync_with_stdio(0);           cin.tie(0);                   //ifstream cin( input.txt );           //ofstream cout( output.txt );                   cin >> t;           while (t--) {               cin >> n;               for (i = 0; i <= n; i++) {                   adj[i].clear(); dadj[i].clear(); visited[i] = false; dist[i] = 0; dp[i] = 0;               }               for (i = 2; i <= n; i++) {                   cin >> v;                   adj[v - 1].push_back(i - 1);                   adj[i - 1].push_back(v - 1);               }                       for (i = 1; i < n; i++) {                   cin >> a[i];               }                       d = 0;               visited[0] = true;               dfs(0);               dadj[0].push_back({0, -1, 0});                       for (i = 1; i <= d; i++) {                   for (auto& u : dadj[i]) {                       u[0] = a[u[2]];                       // cout << u[0] <<     << u[1] <<     << u[2] << endl;                   }                   // cout << endl;                   sort(dadj[i].begin(), dadj[i].end());                   s = dadj[i].size();                   s1 = dadj[i][0][0];                   s2 = dadj[i][dadj[i].size() - 1][0];                   // cout << s1 <<     << s2 << endl;                   for (auto& u : dadj[i]) {                       a1 = a[u[2]];                       dp[u[2]] = max({dp[u[2]], dp[u[1]] + a1 - s1, dp[u[1]] + s2 - a1});                   }                   k = 0;                   for (j = 0; j < s; j++) {                       if (dp[dadj[i][j][1]] - dadj[i][j][0] > dp[dadj[i][k][1]] - dadj[i][k][0]) {                           k = j;                       }                       dp[dadj[i][j][2]] = max(dp[dadj[i][j][2]], dadj[i][j][0] - dadj[i][k][0] + dp[dadj[i][k][1]]);                   }                   k = s - 1;                   for (j = s - 1; j >= 0; j--) {                       if (dp[dadj[i][j][1]] + dadj[i][j][0] > dp[dadj[i][k][1]] + dadj[i][k][0]) {                           k = j;                       }                       dp[dadj[i][j][2]] = max(dp[dadj[i][j][2]], dadj[i][k][0] - dadj[i][j][0] + dp[dadj[i][k][1]]);                   }               }                       res = 0;               for (i = 1; i < n; i++) {                   // cout << dp[i] <<    ;                   res = max(res, dp[i]);               }               // cout << endl;                       cout << res << endl;           }                   return 0;       }