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Submission #375759

# Submission time Handle Problem Language Result Execution time Memory
375759 2021-03-10T00:37:23 Z rama_pang Robot (JOI21_ho_t4) C++14
100 / 100
 1274 ms 88848 KB 
#include <bits/stdc++.h>
using namespace std;

using lint = long long;

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);

  int N, M;
  cin >> N >> M;

  vector<map<int, lint>> S(N);
  vector<map<int, vector<pair<int, int>>>> adj(N);
  for (int i = 0; i < M; i++) {
    int u, v, c, w;
    cin >> u >> v >> c >> w;
    u--, v--;
    S[u][c] += w;
    S[v][c] += w;
    adj[u][c].push_back({v, w});
    adj[v][c].push_back({u, w});
  }

  // Options when traversing an edge:
  // - Change the next road
  //   - Costs P[e]
  // - Change other adjacent road, last road unchanged or has different color
  //   - Costs S[u][C[e]] - P[e]
  // - Change other adjacent road, last road changed and has same color
  //   - Costs S[u][C[e]] - P[e] - P[last]
  //
  // dist[u][0] = minimum cost to vertex u, no restrictions
  // dist[u][c] = minimum cost to vertex u, where the next road must be of color c (use option 3 next)

  vector<map<int, lint>> dist(N);
  priority_queue<array<lint, 3>, vector<array<lint, 3>>, greater<array<lint, 3>>> pq;

  const auto Relax = [&](int u, int c, lint d) {
    if (dist[u].count(c) == 0 || dist[u][c] > d) {
      dist[u][c] = d;
      pq.push({d, u, c});
    }
  };

  Relax(0, 0, 0);
  while (!pq.empty()) {
    lint d = pq.top()[0];
    int u = (int) pq.top()[1];
    int c = (int) pq.top()[2];
    pq.pop();
    if (dist[u][c] != d) {
      continue;
    }
    if (c == 0) {
      for (const auto &adjc : adj[u]) {
        for (const auto &[v, w] : adjc.second) {
          Relax(v, 0, d + w); // Option 1
          Relax(v, 0, d + S[u][adjc.first] - w); // Option 2
          Relax(v, adjc.first, d); // Option 3, Part 1
        }
      }
    } else {
      for (const auto &[v, w] : adj[u][c]) {
        Relax(v, 0, d + S[u][c] - w); // Option 3, Part 2
      }
    }
  }

  cout << (dist[N - 1].count(0) ? dist[N - 1][0] : -1) << '\n';
  return 0;
}

Compilation message

Main.cpp: In function 'int main()':
Main.cpp:57:26: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   57 |         for (const auto &[v, w] : adjc.second) {
      |                          ^
Main.cpp:64:24: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   64 |       for (const auto &[v, w] : adj[u][c]) {
      |                        ^

Subtask #1
34.0 / 34.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 512 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 504 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 2 ms 512 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 5 ms 1132 KB Output is correct
10 Correct 4 ms 1260 KB Output is correct
11 Correct 3 ms 876 KB Output is correct
12 Correct 3 ms 876 KB Output is correct
13 Correct 3 ms 876 KB Output is correct
14 Correct 3 ms 876 KB Output is correct
15 Correct 2 ms 748 KB Output is correct
16 Correct 3 ms 876 KB Output is correct
17 Correct 3 ms 896 KB Output is correct
18 Correct 2 ms 748 KB Output is correct
19 Correct 3 ms 620 KB Output is correct
20 Correct 2 ms 876 KB Output is correct

Subtask #2
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 248 ms 24224 KB Output is correct
2 Correct 104 ms 13220 KB Output is correct
3 Correct 256 ms 18248 KB Output is correct
4 Correct 151 ms 17700 KB Output is correct
5 Correct 1225 ms 86600 KB Output is correct
6 Correct 956 ms 74480 KB Output is correct
7 Correct 420 ms 54472 KB Output is correct
8 Correct 416 ms 52204 KB Output is correct
9 Correct 430 ms 52204 KB Output is correct
10 Correct 401 ms 42024 KB Output is correct
11 Correct 136 ms 28140 KB Output is correct

Subtask #3
42.0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 384 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 512 KB Output is correct
4 Correct 1 ms 384 KB Output is correct
5 Correct 1 ms 504 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 2 ms 512 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 5 ms 1132 KB Output is correct
10 Correct 4 ms 1260 KB Output is correct
11 Correct 3 ms 876 KB Output is correct
12 Correct 3 ms 876 KB Output is correct
13 Correct 3 ms 876 KB Output is correct
14 Correct 3 ms 876 KB Output is correct
15 Correct 2 ms 748 KB Output is correct
16 Correct 3 ms 876 KB Output is correct
17 Correct 3 ms 896 KB Output is correct
18 Correct 2 ms 748 KB Output is correct
19 Correct 3 ms 620 KB Output is correct
20 Correct 2 ms 876 KB Output is correct
21 Correct 248 ms 24224 KB Output is correct
22 Correct 104 ms 13220 KB Output is correct
23 Correct 256 ms 18248 KB Output is correct
24 Correct 151 ms 17700 KB Output is correct
25 Correct 1225 ms 86600 KB Output is correct
26 Correct 956 ms 74480 KB Output is correct
27 Correct 420 ms 54472 KB Output is correct
28 Correct 416 ms 52204 KB Output is correct
29 Correct 430 ms 52204 KB Output is correct
30 Correct 401 ms 42024 KB Output is correct
31 Correct 136 ms 28140 KB Output is correct
32 Correct 156 ms 11116 KB Output is correct
33 Correct 206 ms 18020 KB Output is correct
34 Correct 520 ms 42524 KB Output is correct
35 Correct 395 ms 34076 KB Output is correct
36 Correct 371 ms 48792 KB Output is correct
37 Correct 412 ms 51028 KB Output is correct
38 Correct 478 ms 60632 KB Output is correct
39 Correct 170 ms 15204 KB Output is correct
40 Correct 426 ms 53484 KB Output is correct
41 Correct 477 ms 53612 KB Output is correct
42 Correct 616 ms 61208 KB Output is correct
43 Correct 277 ms 25380 KB Output is correct
44 Correct 526 ms 26784 KB Output is correct
45 Correct 375 ms 50284 KB Output is correct
46 Correct 302 ms 50156 KB Output is correct
47 Correct 420 ms 50896 KB Output is correct
48 Correct 1274 ms 88848 KB Output is correct