#include using namespace std; using lint = long long int; using pint = pair; struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; #define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i=i##_begin_;i--) #define REP(i, n) FOR(i,0,n) #define IREP(i, n) IFOR(i,0,n) template istream &operator>>(istream &is, vector &vec){ for (auto &v : vec) is >> v; return is; } #define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl; class UndirectedWeightedTree { using T = lint; // operator+, operator- must be defined const int INVALID = -1; int V, lgV; int E; int root; vector> adj; // (nxt_vertex, edge_id) // vector edge; // edges[edge_id] = (vertex_id, vertex_id) vector weight; // w[edge_id] vector par; // parent_vertex_id[vertex_id] vector depth; // depth_from_root[vertex_id] vector acc_weight; // w_sum_from_root[vertex_id] void _fix_root_dfs(int now, int prv, int prv_edge_id) { par[now] = prv; if (prv_edge_id != INVALID) acc_weight[now] = acc_weight[prv] + weight[prv_edge_id]; for (auto nxt : adj[now]) if (nxt.first != prv) { depth[nxt.first] = depth[now] + 1; _fix_root_dfs(nxt.first, now, nxt.second); } } public: UndirectedWeightedTree(int N = 0): V(N), E(0), adj(N) { lgV = 1; while (1 << lgV < V) lgV++; } void add_edge(int u, int v, T w) { adj[u].emplace_back(v, E); adj[v].emplace_back(u, E); // edge.emplace_back(u, v); weight.emplace_back(w); E++; } void fix_root(int r) { root = r; par.resize(V); depth.assign(V, 0); acc_weight.resize(V); _fix_root_dfs(root, INVALID, INVALID); } vector> doubling; void doubling_precalc() { doubling.assign(lgV, vector(V)); doubling[0] = par; REP(d, lgV - 1) REP(i, V) { if (doubling[d][i] == INVALID) doubling[d + 1][i] = INVALID; else doubling[d + 1][i] = doubling[d][doubling[d][i]]; } } int kth_parent(int x, int k) { REP(d, lgV) { if (x == INVALID) return INVALID; if (k & (1 << d)) x = doubling[d][x]; } return x; } int lowest_common_ancestor(int u, int v) { if (depth[u] > depth[v]) swap(u, v); v = kth_parent(v, depth[v] - depth[u]); if (u == v) return u; IREP(d, lgV) { if (doubling[d][u] != doubling[d][v]) u = doubling[d][u], v = doubling[d][v]; } return par[u]; } T path_length(int u, int v) { int r = lowest_common_ancestor(u, v); return (acc_weight[u] - acc_weight[r]) + (acc_weight[v] - acc_weight[r]); } }; int main() { int N; cin >> N; UndirectedWeightedTree g(N); REP(_, N - 1) { int u, v, w; cin >> u >> v >> w; g.add_edge(u, v, w); } g.fix_root(0); g.doubling_precalc(); int Q; cin >> Q; REP(_, Q) { int x, y, z; cin >> x >> y >> z; int xy = g.lowest_common_ancestor(x, y); int xyz = g.lowest_common_ancestor(xy, z); if (xy != xyz) { cout << g.path_length(xy, z) + g.path_length(x, y) << endl; } else { int v = g.lowest_common_ancestor(x, z) + g.lowest_common_ancestor(y, z) - xy; cout << g.path_length(x, y) + g.path_length(z, v) << endl; } } }