Submission #653419

#	Time	Username	Problem	Language	Result	Execution time	Memory
653419		tvladm2009	Cities (BOI16_cities)	C++14	100 / 100	2512 ms	51040 KiB

cities

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
#define int ll
const int N = (int) 2e5 + 7;
const int K = 5;
const int INF = (ll) 1e18;
int dp[1 << K][N], special[N];
vector<pair<int, int>> g[N];
bool vis[N];
int n, k, m;

signed main() {
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);

  cin >> n >> k >> m;
  vector<int> cities(k + 1);
  for (int i = 1; i <= k; i++) {
    cin >> cities[i];
    special[cities[i]] = i;
  }
  for (int i = 1; i <= m; i++) {
    int x, y, z;
    cin >> x >> y >> z;
    g[x].push_back({y, z});
    g[y].push_back({x, z});
  }
  for (int mask = 0; mask < (1 << k); mask++) {
    for (int i = 0; i <= n; i++) {
      dp[mask][i] = INF;
    }
  }
  for (int i = 1; i <= k; i++) {
    dp[(1 << (i - 1))][cities[i]] = 0;
  }
  for (int i = 1; i <= n; i++) {
    dp[0][i] = 0;
  }

  for (int mask = 0; mask < (1 << k); mask++) {
    for (int i = 1; i <= n; i++) {
      for (int submask = mask; submask > 0; submask = (submask - 1) & mask) {
        ll newmask = (mask ^ submask);
        if (special[i]) {
          newmask ^= (1 << (special[i] - 1));
        }
        dp[mask][i] = min(dp[mask][i], dp[newmask][i] + dp[submask][i]);
      }
    }

    priority_queue<pair<int, int>> pq;
    for (int i = 0; i <= n; i++) {
      vis[i] = 0;
      pq.push({-dp[mask][i], i});
    }
    while (!pq.empty()) {
      pair<int, int> u = pq.top();
      pq.pop();
      if (vis[u.second]) {
        continue;
      }
      vis[u.second] = 1;
      for (auto &v : g[u.second]) {
        if (dp[mask][u.second] + v.second < dp[mask][v.first]) {
          dp[mask][v.first] = dp[mask][u.second] + v.second;
          pq.push({-dp[mask][v.first], v.first});
        }
      }
    }
  }
  ll ret = INF;
  for (int i = 0; i <= n; i++) {
    ret = min(ret, dp[(1 << k) - 1][i]);
  }
  cout << ret;
  return 0;
}

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