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Submission #601355

# Submission time Handle Problem Language Result Execution time Memory
601355 2022-07-21T18:17:48 Z narvalo Ferries (NOI13_ferries) C++17
17 / 40
 144 ms 19144 KB 
#include <bits/stdc++.h>

using namespace std;

const int INF = (int)1e9;

int ferries(int n , int m , vector<int> a , vector<int> b , vector<int> c) {
  vector<vector<pair<int , int>>> adj(n);
  for (int i = 0 ; i < m ; i++) {
    a[i] -= 1 , b[i] -= 1;
    adj[a[i]].emplace_back(b[i] , c[i]);
  }
  vector<int> dp(n , -1) , vis(n);
  function<int(int)> Solve = [&](int node) {
    if (node == n - 1) {
      return 0;
    }
    if (vis[node] == 1) {
      return -1;
    }
    if (dp[node] != -1) {
      return dp[node];
    }
    vis[node] = 1;
    vector<int> d , s;
    for (auto x : adj[node]) {
      int g = Solve(x.first);
      if (g != -1 && g != INF) {
        d.emplace_back(g);
        s.emplace_back(x.second);
      }
    }
    sort(d.begin() , d.end());
    sort(s.begin() , s.end());
    auto Get = [&]() {
      int val = INF;
      for (int i = 0 ; i < (int)s.size() ; i += 1) {
        val = min(val , s[i] + d[(int)s.size() - i - 1]);
      }
      return val;
    };
    int res = Get();
    reverse(s.begin() , s.end());
    reverse(d.begin() , d.end());
    res = max(res , Get());
    vis[node] = 2;
    return dp[node] = res;
  };
  int res = Solve(0);
  return res;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n , m;
  cin >> n >> m;
  vector<int> a(m) , b(m) , c(m);
  for (int i = 0 ; i < m ; i += 1) {
    cin >> a[i] >> b[i] >> c[i];
  }
  cout << ferries(n , m , a , b , c) << '\n';
}

Subtask #1
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 2 ms 468 KB Output is correct
3 Correct 11 ms 1720 KB Output is correct
4 Correct 94 ms 13428 KB Output is correct
5 Correct 87 ms 13336 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 320 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 9 ms 1748 KB Output is correct
4 Correct 44 ms 7052 KB Output is correct
5 Correct 56 ms 9676 KB Output is correct

Subtask #3
0 / 11.0

# Verdict Execution time Memory Grader output
1 Incorrect 15 ms 2124 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 12.0

# Verdict Execution time Memory Grader output
1 Incorrect 144 ms 19144 KB Output isn't correct
2 Halted 0 ms 0 KB -