Submission #1093106

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093106		juicy	Cities (BOI16_cities)	C++17	100 / 100	1382 ms	41584 KiB

cities

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

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

  const long long inf = 1e18;

  int n, k, m; cin >> n >> k >> m;
  vector<int> city(k);
  for (int &u : city) {
    cin >> u; --u;
  }
  vector<vector<array<int, 2>>> g(n);
  while (m--) {
    int u, v, c; cin >> u >> v >> c; --u, --v;
    g[u].push_back({v, c});
    g[v].push_back({u, c});
  }
  auto dijkstra = [&](vector<long long> &d) {
    using T = pair<long long, int>;
    priority_queue<T, vector<T>, greater<T>> pq;
    for (int i = 0; i < n; ++i) {
      pq.push({d[i], i});
    }
    while (pq.size()) {
      auto [c, u] = pq.top(); pq.pop();
      if (c != d[u]) {
        continue;
      }
      for (auto [v, w] : g[u]) {
        if (d[v] > c + w) {
          pq.push({d[v] = c + w, v});
        }
      }
    }
    return d;
  };
  vector d(1 << k, vector<long long>(n, inf));
  for (int i = 0; i < k; ++i) {
    d[1 << i][city[i]] = 0;
  }
  for (int m = 1; m < 1 << k; ++m) {
    for (int i = 0; i < k; ++i) {
      if (m >> i & 1) {
        for (int j = 0; j < n; ++j) {
          d[m][j] = min(d[m][j], d[m - (1 << i)][j] + d[1 << i][j]);
        }
      }
    }
    dijkstra(d[m]);
  }
  long long res = inf;
  for (int i = 0; i < k; ++i) {
    res = min(res, d.back()[city[i]]);
  }
  cout << res;
  return 0;
}

• Subtask 1: 22 / 22
• Subtask 2: 14 / 14
• Subtask 3: 15 / 15
• Subtask 4: 23 / 23
• Subtask 5: 26 / 26