// File C.cpp created on 01.12.2025 at 14:24:02 #include <bits/stdc++.h> using i64 = long long; #ifdef DEBUG #include "/home/ahmetalp/Desktop/Workplace/debug.h" #else #define debug(...) void(23) #endif constexpr int md = int(1E9) + 7; int add(int x, int y) { x += y; if (x >= md) { x -= md; } return x; } int sub(int x, int y) { x -= y; if (x < 0) { x += md; } return x; } int mul(int x, int y) { return 1LL * x * y % md; } #define def int mid = (l + r) >> 1, lv = v + 1, rv = v + ((mid - l + 1) << 1) struct segtree { struct node { int siz = 1; i64 act = 0; int sum = 0; i64 lz = 0; node() {} node(i64 x) : act(x), sum(x % md) {} void modify(i64 x) { act += x; sum = add(sum, mul(x % md, siz)); lz += x; } }; node unite(const node& lhs, const node& rhs) { node res; res.siz = lhs.siz + rhs.siz; res.sum = add(lhs.sum, rhs.sum); return res; } int n; std::vector<node> tree; segtree() {} void init(int n_) { n = n_; tree.resize(n << 1); auto dfs = [&](auto&& self, int v, int l, int r) -> void { if (l == r) { return; } def; self(self, lv, l, mid); self(self, rv, mid + 1, r); tree[v] = unite(tree[lv], tree[rv]); }; dfs(dfs, 0, 0, n - 1); } void push(int v, int l, int r) { def; tree[lv].modify(tree[v].lz); tree[rv].modify(tree[v].lz); tree[v].lz = 0; } void set(int v, int l, int r, int p, i64 x) { if (l == r) { tree[v] = x; return; } def; push(v, l, r); if (p <= mid) { set(lv, l, mid, p, x); } else { set(rv, mid + 1, r, p, x); } tree[v] = unite(tree[lv], tree[rv]); } void set(int p, i64 x) { set(0, 0, n - 1, p, x); } void modify(int v, int l, int r, int ql, int qr, i64 x) { if (ql == l && r == qr) { tree[v].modify(x); return; } def; push(v, l, r); if (qr <= mid) { modify(lv, l, mid, ql, qr, x); } else if (mid + 1 <= ql) { modify(rv, mid + 1, r, ql, qr, x); } else { modify(lv, l, mid, ql, mid, x); modify(rv, mid + 1, r, mid + 1, qr, x); } tree[v] = unite(tree[lv], tree[rv]); } void modify(int l, int r, i64 x) { modify(0, 0, n - 1, l, r, x); } i64 get(int v, int l, int r, int p) { if (l == r) { return tree[v].act; } def; push(v, l, r); if (p <= mid) { return get(lv, l, mid, p); } else { return get(rv, mid + 1, r, p); } } i64 get(int p) { return get(0, 0, n - 1, p); } int sum() { return tree[0].sum; } } seg; int N; std::vector<int> par; std::vector<i64> dis; std::vector<std::vector<int>> adj; std::vector<i64> mx2; std::vector<int> heavy; std::vector<int> siz; std::vector<int> top; std::vector<int> tin; std::vector<int> tout; std::vector<int> tour; int tim; void dfs1(int v) { siz[v] = 1; for (auto& u : adj[v]) { heavy[v] = u; dfs1(u); siz[v] += siz[u]; if (siz[u] > siz[adj[v][0]]) { std::swap(u, adj[v][0]); } } } void dfs2(int v) { tour[tim] = v; tin[v] = tim++; for (auto u : adj[v]) { top[u] = (u == adj[v][0] ? top[v] : u); dfs2(u); } tout[v] = tim; } void init() { dfs1(0); dfs2(0); } i64 ans = 0; void upd(int v, i64 x) { debug(v, x); while (v != 0) { int u = par[v]; debug(v, u); if (heavy[u] == v) { seg.modify(tin[u], tin[u], x); } else { i64 dv = seg.get(tin[v]); i64 du = seg.get(tin[u]); debug(dv, du); if (dv + dis[v] > du) { ans -= mx2[u]; mx2[u] = du; ans += mx2[u]; seg.set(tin[u], dv + dis[v]); x = dv + dis[v] - du; heavy[u] = v; } else if (dv + dis[v] > mx2[u]) { ans -= mx2[u]; mx2[u] = dv + dis[v]; ans += mx2[u]; break; } else { break; } } v = u; } } int main() { std::ios::sync_with_stdio(false); std::cin.tie(nullptr); std::cin >> N; par.resize(N); dis.resize(N); adj.resize(N); seg.init(N); mx2.resize(N); heavy.resize(N); top.resize(N); siz.resize(N); tin.resize(N); tout.resize(N); tour.resize(N); for (int i = 1; i < N; ++i) { std::cin >> par[i]; adj[par[i]].emplace_back(i); } init(); for (int i = 1; i < N; ++i) { std::cin >> dis[i]; upd(i, dis[i]); } std::cout << add(ans % md, seg.sum()) << '\n'; int Q; std::cin >> Q; while (Q--) { int v, x; std::cin >> v >> x; dis[v] += x; upd(v, x); std::cout << add(ans % md, seg.sum()) << '\n'; #ifdef LOCAL debug(ans, seg.sum(), mx2); #endif } return 0; }