#include <bits/stdc++.h> #define ll long long #define task "RELAYMARATHON" using namespace std; const int N = 1e5 + 16; const ll INF = 1e18; int n, m, K, u, v, a[N]; ll w, result; vector < pair <int, ll> > adj[N]; namespace sub4 { ll d[N]; priority_queue < pair <ll, int>, vector < pair <ll, int> >, greater < pair <ll, int> > > pq; void dijkstra(int k) { for (int i = 1; i <= n; i++) { d[i] = INF; } d[k] = 0; pq.push({d[k], k}); while (!pq.empty()) { pair <ll, int> top = pq.top(); pq.pop(); ll dist = top.first; int u = top.second; if (dist > d[u]) { continue; } for (auto v : adj[u]) { int vertex = v.first; ll value = v.second; if (d[vertex] > dist + value) { d[vertex] = dist + value; pq.push({d[vertex], vertex}); } } } } int s1 = -1, e1 = -1, s2 = -1, e2 = -1; void solve() { dijkstra(a[1]); for (int i = 1; i <= K; i++) { if (a[i] == a[1]) { continue; } if (s1 == -1 || d[s1] > d[a[i]]) { s1 = a[i]; } } dijkstra(s1); for (int i = 1; i <= K; i++) { if (a[i] == s1) { continue; } if (e1 == -1 || d[e1] > d[a[i]]) { e1 = a[i]; } } result += d[e1]; int root = -1; for (int i = 1; i <= K; i++) { if (a[i] == s1 || a[i] == e1) { continue; } root = a[i]; break; } dijkstra(root); for (int i = 1; i <= K; i++) { if (a[i] == s1 || a[i] == e1) { continue; } if (s2 == -1 || d[s2] > d[a[i]]) { s2 = a[i]; } } dijkstra(s2); for (int i = 1; i <= K; i++) { if (a[i] == s1 || a[i] == e1) { continue; } if (a[i] == s2) { continue; } if (e2 == -1 || d[e2] > d[a[i]]) { e2 = a[i]; } } result += d[e2]; cout << result; } } int main() { ios_base :: sync_with_stdio(false); cin.tie(0); cout.tie(0); if (fopen(task".inp", "r")) { freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); } cin >> n >> m >> K; for (int i = 1; i <= m; i++) { cin >> u >> v >> w; adj[u].push_back({v, w}); adj[v].push_back({u, w}); } for (int i = 1; i <= K; i++) { cin >> a[i]; } sub4 :: solve(); return 0; }

RelayMarathon.cpp: In function 'int main()':
RelayMarathon.cpp:107:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
RelayMarathon.cpp:108:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  108 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~