oj.uz

Submission #201642

# Submission time Handle Problem Language Result Execution time Memory
201642 2020-02-11T14:07:10 Z waynetuinfor Olympic Bus (JOI20_ho_t4) C++17
0 / 100
 103 ms 1952 KB 
#include <algorithm>
#include <array>
#include <iostream>
#include <queue>
#include <vector>

int main() {
  int n, m;
  std::cin >> n >> m;
  constexpr int kInf = 1'000'000'000;
  std::vector<std::vector<int>> dist(n, std::vector<int>(n, kInf));
  for (int i = 0; i < n; ++i) dist[i][i] = 0;
  std::vector<std::array<int, 4>> ed(m);
  std::vector<std::vector<std::pair<int, int>>> g(n);
  for (int i = 0; i < m; ++i) {
    int u, v, c, d;
    std::cin >> u >> v >> c >> d;
    u--, v--;
    dist[u][v] = std::min(dist[u][v], c);
    ed[i] = {u, v, c, d};
    g[u].emplace_back(v, i);
  }
  for (int k = 0; k < n; ++k) {
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < n; ++j) {
        dist[i][j] = std::min(dist[i][j], dist[i][k] + dist[k][j]);
      }
    }
  }
  int ans = dist[0][n - 1] + dist[n - 1][0];

  auto Dijkstra = [&](int s, int e, int v) {
    std::vector<int> dist(n, kInf), used(n);
    std::priority_queue<std::pair<int, int>> pq;
    pq.emplace(0, s);
    dist[s] = 0;
    while (!pq.empty()) {
      int x = pq.top().second;
      pq.pop();
      if (x == e) break;
      if (used[x]++) continue;
      for (auto i : g[x]) {
        int u = i.first, z = i.second;
        if (z == v) continue;
        if (dist[u] > dist[x] + ed[z][2]) {
          dist[u] = dist[x] + ed[z][2];
          pq.emplace(-dist[u], u);
        }
      }
      if (x == ed[v][1]) {
        if (dist[ed[v][0]] > dist[x] + ed[v][2]) {
          dist[ed[v][0]] = dist[x] + ed[v][2];
          pq.emplace(-dist[ed[v][0]], ed[v][0]);
        }
      }
    }
    return dist[e];
  };

  for (int i = 0; i < m; ++i) {
    int u = ed[i][0], v = ed[i][1], c = ed[i][2], d = ed[i][3];
    int a = std::min(dist[0][n - 1], dist[0][v] + dist[u][n - 1] + c);
    int b = std::min(dist[n - 1][0], dist[n - 1][v] + dist[u][0] + c);
    if (a + b + d < ans) {
      int x = Dijkstra(0, n - 1, i);
      int y = Dijkstra(n - 1, 0, i);
      ans = std::min(ans, x + y + d);
    }
  }
  if (ans >= kInf) ans = -1;
  std::cout << ans << "\n";
  return 0;
}

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 504 KB Output is correct
2 Incorrect 15 ms 504 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 98 ms 1916 KB Output is correct
2 Correct 91 ms 1952 KB Output is correct
3 Correct 102 ms 1912 KB Output is correct
4 Correct 18 ms 504 KB Output is correct
5 Correct 16 ms 504 KB Output is correct
6 Correct 15 ms 504 KB Output is correct
7 Correct 14 ms 504 KB Output is correct
8 Correct 5 ms 256 KB Output is correct
9 Incorrect 103 ms 1912 KB Output isn't correct
10 Halted 0 ms 0 KB -

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 504 KB Output is correct
2 Correct 14 ms 504 KB Output is correct
3 Correct 70 ms 1528 KB Output is correct
4 Incorrect 14 ms 504 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 504 KB Output is correct
2 Incorrect 15 ms 504 KB Output isn't correct
3 Halted 0 ms 0 KB -