Submission #1049550

#	Time	Username	Problem	Language	Result	Execution time	Memory
1049550		avighna	Relay Marathon (NOI20_relaymarathon)	C++17	25 / 100	773 ms	247840 KiB

RelayMarathon

#include <bits/stdc++.h>

typedef long long ll;

const ll inf = 1e15;

struct Edge {
  ll u, v, w;
};

int main() {
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(nullptr);

  ll n, m, k;
  std::cin >> n >> m >> k;
  std::vector<std::vector<std::pair<ll, ll>>> adj(n + 1);
  std::vector<Edge> edges;
  for (ll i = 0, u, v, w; i < m; ++i) {
    std::cin >> u >> v >> w;
    adj[u].push_back({v, w});
    adj[v].push_back({u, w});
    edges.push_back({u, v, w});
  }
  std::vector<ll> A(k);
  std::vector<bool> special(n + 1);
  std::priority_queue<std::pair<ll, std::pair<ll, ll>>> pq;
  std::vector<ll> d(n + 1, inf);
  for (auto &i : A) {
    std::cin >> i;
    special[i] = true;
    pq.push({0, {i, i}});
    d[i] = 0;
  }

  std::vector<std::pair<ll, ll>> closest_special(n + 1);
  std::vector<bool> vis(n + 1);
  while (!pq.empty()) {
    ll node = pq.top().second.first, source = pq.top().second.second,
       dist = -pq.top().first;
    pq.pop();
    if (vis[node]) {
      continue;
    }
    vis[node] = true;
    closest_special[node] = {source, dist};
    for (auto &[i, i_d] : adj[node]) {
      if (dist + i_d < d[i]) {
        d[i] = dist + i_d;
        pq.push({-d[i], {i, source}});
      }
    }
  }

  ll ans = inf;
  for (auto &[u, v, w] : edges) {
    if (u != 1 and u != 2 and v != 1 and v != 2 and special[u] and special[v]) {
      ans = std::min(ans, w);
    }
  }
  for (auto &[u, v, w] : edges) {
    if (u == 1 or u == 2 or v == 1 or v == 2) {
      continue;
    }
    if (closest_special[u].first != closest_special[v].first) {
      ans = std::min(ans,
                     closest_special[u].second + w + closest_special[v].second);
    }
  }
  std::cout << ans + 1 << '\n';
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 12
• Subtask 3: 25 / 25
• Subtask 4: 0 / 58