제출 #981149

#제출 시각아이디문제언어결과실행 시간메모리
981149aaaaaarrozCommuter Pass (JOI18_commuter_pass)C++17
100 / 100
198 ms22564 KiB
    #include <bits/stdc++.h>
     
    #define nl '\n'
     
    template <typename T> 
    inline bool ckmin(T& x, const T& y) {
      return y < x ? x = y, 1 : 0;
    }
     
     
    signed main() {
      std::ios::sync_with_stdio(false);
      std::cin.tie(nullptr);
      
      int N, M, S, T, U, V;
      std::cin >> N >> M >> S >> T >> U >> V;
      --S, --T, --U, --V;
     
      std::vector<std::vector<std::pair<int, int>>> adj(N);
     
      for (int i = 0; i < M; i++) {
        int u, v, w;
        std::cin >> u >> v >> w;
        --u, --v;
        adj[u].emplace_back(v, w);
        adj[v].emplace_back(u, w);
      }
     
      auto dijkstra = [&](int st) -> std::vector<int64_t> {
        std::vector<int64_t> dp(N, 1e18);
        dp[st] = 0;
     
        std::priority_queue<std::pair<int64_t, int>> pq;
        pq.emplace(dp[st], st);
     
        while (pq.size()) {
          auto [d, u] = pq.top();
          pq.pop();
     
          d = -d;
     
          if (dp[u] < d) continue;
     
          for (auto [v, w] : adj[u]) {
            auto nd = d + w;
            if (nd < dp[v]) {
              dp[v] = nd;
              pq.emplace(-dp[v], v);
            }
          }
        }
     
        return dp;
      };
     
      auto dpU = dijkstra(U);
      auto dpV = dijkstra(V);
     
      auto dijkstra2 = [&](int st, std::vector<int64_t>& minU,
                           std::vector<int64_t>& minV) -> std::vector<int64_t> {
     
        std::vector<int64_t> dp(N, 1e18);
        dp[st] = 0;
     
        minU.assign(N, 1e18);
        minV.assign(N, 1e18);
     
        std::priority_queue<std::pair<int64_t, int>> pq;
        pq.emplace(dp[st], st);
     
        while (pq.size()) {
          auto [d, u] = pq.top();
          pq.pop();
     
          d = -d;
     
          if (dp[u] < d) continue;
     
          ckmin(minU[u], dpU[u]);
          ckmin(minV[u], dpV[u]);          
     
          for (auto [v, w] : adj[u]) {
            auto nd = d + w;
            if (nd == dp[v]) {
              ckmin(minU[v], minU[u]);
              ckmin(minV[v], minV[u]);
            } else if (nd < dp[v]) {
              minU[v] = minU[u];
              minV[v] = minV[u];
              dp[v] = nd;
              pq.emplace(-dp[v], v);
            }
          }
        }
     
        return dp;
      };
     
     
      std::vector<int64_t> minSU, minSV, minTU, minTV;
     
      auto dpS = dijkstra2(S, minSU, minSV);
      auto dpT = dijkstra2(T, minTU, minTV);
     
      int64_t ans = dpU[V];
      for (int i = 0; i < N; i++) {
        if (dpS[i] + dpT[i] == dpS[T]) {
          // this is an edge 
          ckmin(ans, minSU[i] + minTV[i]);
          ckmin(ans, minSV[i] + minTU[i]);
        }
      }
     
      std::cout << ans << nl;
    }
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...