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Submission #1082983

# Submission time Handle Problem Language Result Execution time Memory
1082983 2024-09-02T09:32:32 Z avighna Aesthetic (NOI20_aesthetic) C++17
35 / 100
 2000 ms 55528 KB 
#include <bits/stdc++.h>

typedef long long ll;

struct To {
  ll v, w;
  ll i;
};

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

const ll inf = 1e15;

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

  ll n, m;
  std::cin >> n >> m;
  std::vector<std::vector<To>> 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, i});
    adj[v].push_back({u, w, i});
    edges.push_back({u, v, w});
  }

  auto sssp = [&](ll node) {
    std::vector<ll> ans(n + 1, inf);
    std::vector<bool> vis(n + 1);
    std::priority_queue<std::pair<ll, ll>> pq;
    ans[node] = 0;
    pq.push({0, node});
    while (!pq.empty()) {
      auto [d, node] = pq.top();
      d *= -1;
      pq.pop();
      if (vis[node]) {
        continue;
      }
      vis[node] = true;
      for (auto [ch, w, cur_i] : adj[node]) {
        if (ans[ch] > d + w) {
          ans[ch] = d + w;
          pq.push({-ans[ch], ch});
        }
      }
    }
    return ans;
  };

  auto sssp1 = sssp(1);
  auto ssspn = sssp(n);

  auto check = [&](ll x) {
    std::vector<bool> active_edge(m);
    for (ll i = 0; i < m; ++i) {
      auto [u, v, w] = edges[i];
      if (sssp1[u] + w + ssspn[v] <= x or sssp1[v] + w + ssspn[u] <= x) {
        active_edge[i] = true;
      }
    }
    std::vector<bool> is_bridge(m), vis(n + 1), enc(n + 1);
    enc[n] = true;
    std::vector<ll> low(n + 1), tin(n + 1);
    ll timer = 0;
    std::function<void(ll, ll)> dfs;
    dfs = [&](ll node, ll par) {
      if (vis[node]) {
        return;
      }
      vis[node] = true;
      tin[node] = timer++;
      low[node] = tin[node];
      for (auto &[ch, w, i] : adj[node]) {
        if (ch == par or !active_edge[i]) {
          continue;
        }
        if (!vis[ch]) {
          dfs(ch, node);
          enc[node] = enc[node] || enc[ch];
        }
        is_bridge[i] = low[ch] > tin[node] and enc[ch];
        low[node] = std::min(low[node], low[ch]);
      }
    };
    dfs(1, 0);
    ll worst_road = edges[m - 1].w;
    for (ll i = m - 2; i >= 0; --i) {
      auto [u, v, w] = edges[i];
      if (is_bridge[i] and
          std::min(sssp1[u] + ssspn[v], sssp1[v] + ssspn[u]) + w + worst_road >
              x) {
        return true;
      }
      worst_road = std::max(worst_road, edges[i].w);
    }
    return false;
  };

  ll s = sssp1[n], e = 1e15;
  while (s < e) {
    ll m = s + (e - s) / 2;
    if (check(m)) {
      s = m + 1;
    } else {
      e = m;
    }
  }
  std::cout << s << '\n';
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 600 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct

Subtask #2
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 600 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 2 ms 600 KB Output is correct
10 Correct 2 ms 604 KB Output is correct
11 Correct 2 ms 604 KB Output is correct
12 Correct 2 ms 604 KB Output is correct
13 Correct 2 ms 604 KB Output is correct
14 Correct 2 ms 604 KB Output is correct
15 Correct 2 ms 604 KB Output is correct
16 Correct 2 ms 604 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 936 ms 44224 KB Output is correct
2 Correct 888 ms 44400 KB Output is correct
3 Correct 874 ms 43756 KB Output is correct
4 Correct 882 ms 44004 KB Output is correct
5 Correct 952 ms 44020 KB Output is correct
6 Correct 926 ms 45072 KB Output is correct
7 Correct 931 ms 44888 KB Output is correct
8 Correct 918 ms 45032 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 946 ms 45032 KB Output is correct
2 Correct 941 ms 44260 KB Output is correct
3 Correct 842 ms 44520 KB Output is correct
4 Correct 846 ms 45036 KB Output is correct
5 Correct 909 ms 44264 KB Output is correct
6 Correct 890 ms 44448 KB Output is correct
7 Correct 920 ms 44156 KB Output is correct
8 Correct 1006 ms 44608 KB Output is correct

Subtask #5
0 / 16.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2053 ms 55528 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 22.0

# Verdict Execution time Memory Grader output
1 Execution timed out 2053 ms 55528 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #7
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 600 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 2 ms 600 KB Output is correct
10 Correct 2 ms 604 KB Output is correct
11 Correct 2 ms 604 KB Output is correct
12 Correct 2 ms 604 KB Output is correct
13 Correct 2 ms 604 KB Output is correct
14 Correct 2 ms 604 KB Output is correct
15 Correct 2 ms 604 KB Output is correct
16 Correct 2 ms 604 KB Output is correct
17 Correct 936 ms 44224 KB Output is correct
18 Correct 888 ms 44400 KB Output is correct
19 Correct 874 ms 43756 KB Output is correct
20 Correct 882 ms 44004 KB Output is correct
21 Correct 952 ms 44020 KB Output is correct
22 Correct 926 ms 45072 KB Output is correct
23 Correct 931 ms 44888 KB Output is correct
24 Correct 918 ms 45032 KB Output is correct
25 Correct 946 ms 45032 KB Output is correct
26 Correct 941 ms 44260 KB Output is correct
27 Correct 842 ms 44520 KB Output is correct
28 Correct 846 ms 45036 KB Output is correct
29 Correct 909 ms 44264 KB Output is correct
30 Correct 890 ms 44448 KB Output is correct
31 Correct 920 ms 44156 KB Output is correct
32 Correct 1006 ms 44608 KB Output is correct
33 Execution timed out 2053 ms 55528 KB Time limit exceeded
34 Halted 0 ms 0 KB -