#include <bits/stdc++.h> #define int long long using namespace std; const long long N = 2e5 + 5; const long long lg = 20; int a[N]; int start[N]; int en[N]; int weight[N]; int tim = 0; int p[N]; int nearest[N]; vector<pair<int, int>> graph[N]; vector<pair<int, int>> edges; int sp[N][lg]; int st[N][lg]; // const int N = 2e5 + 3; int dist[N]; int mask; void go_up(int &k, int binary) { for (int i = 0; i < lg; i++) { mask = 1LL << i; if ((binary & mask) != 0) { k = sp[k][i]; } } } int same_at_height(int u, int v) { if (u == v) return v; for (int i = lg - 1; i >= 0; i--) { if (sp[u][i] != sp[v][i]) { u = sp[u][i]; v = sp[v][i]; } } return sp[u][0]; } int lca(int u, int v) { if (dist[u] > dist[v]) swap(u, v); // cout << u << ' ' << v << endl; // cout << dist[u] << ' ' << dist[v] << endl; int diff = dist[v] - dist[u]; go_up(v, diff); // cout << u << ' ' << v << endl; if (u == v) return u; return same_at_height(u, v); } // Function to initialize the Sparse Table void initialize(int n) { // int n = ls.size(); for (int i = 0; i <= n; i++) { sp[i][0] = p[i]; st[i][0] = nearest[i] - weight[i]; } for (int i = 1; i < lg; i++) { for (int j = 0; j <= n; j++) { st[j][i] = min(st[j][i - 1], st[sp[j][i - 1]][i - 1]); sp[j][i] = sp[sp[j][i - 1]][i - 1]; } } } int get(int l, int r) { // l=st[l][0]; int ans = 1e18; // get rth ancestor of l for (int i = lg - 1; i >= 0; i--) { if ((r >> i) & 1) { ans = min(ans, st[l][i]); l = sp[l][i]; } } return ans; } void dfs(int node, int parent) { // cout << "visited " << node << endl; p[node] = parent; start[node] = tim++; dist[node] = dist[parent] + 1; for (auto i : graph[node]) { if (i.first == parent) continue; weight[i.first] = i.second + weight[node]; dfs(i.first, node); // cout << node << " " << i.first << ' ' << nearest[i.first] << ' ' << i.second << endl; nearest[node] = min(nearest[node], nearest[i.first] + i.second); } en[node] = tim; } void solve() { int n, s, q, E; int e; cin >> n >> s >> q >> E; int u, v, w; for (int i = 1; i < n; i++) { cin >> u >> v >> w; edges.push_back({u, v}); graph[u].push_back({v, w}); graph[v].push_back({u, w}); } fill(nearest, nearest + N, 1e15); for (int i = 0; i < s; i++) { // shops cin >> e; nearest[e] = 0; } dfs(E, 0); initialize(n + 1); // int q; // cin >> q; // for (int i = 0; i < n; i++) // { // cout << st[i + 1][0] << ' '; // } // cout << endl; for (int i = 0; i < q; i++) { cin >> u >> v; u--; int tutau; // road u is cut if (start[edges[u].first] > start[edges[u].second]) swap(edges[u].first, edges[u].second); tutau = edges[u].second; // cout << lca(3, 5) << endl; // cout << sp[5][0] << endl; if (lca(tutau, v) != tutau) { cout << "escaped\n"; continue; } // cout << tutau << ' ' << edges[u].second << ' ' << v << endl; int up = dist[v] - dist[tutau]; // cout << dist[v] << ' ' << dist[tutau] << endl; // / // cout << up << endl; // cout << p[5] << endl; // cout << st[5][1] << endl; int ans = get(v, up + 1) + weight[v]; if (ans == 1e15) { cout << "oo" << endl; } else { cout << ans << endl; } } } signed main() { ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL); int t = 1; // cin >> t; for (int i = 1; i <= t; i++) { // cout << "Case #" << i << ':' << ' '; solve(); cout << endl; } return 0; }