Submission #1293273

#	Time	Username	Problem	Language	Result	Execution time	Memory
1293273		madamadam3	Cities (BOI16_cities)	C++20	100 / 100	1313 ms	69684 KiB

cities

#include <bits/stdc++.h>
 
using namespace std;

typedef long long ll;
using pi = pair<ll, int>;
 
const ll INF = 4e18;
 
int n, k, m;
vector<vector<pi>> adj;
vector<int> imp;
 
int main() {
    cin.tie(0)->sync_with_stdio(0);
 
    cin >> n >> k >> m;
    adj.assign(n+1, vector<pi>()); 
    imp.resize(k); for (int i = 0; i < k; i++) cin >> imp[i];
    for (int i = 0; i < m; i++) {int x, y, c; cin >> x >> y >> c; adj[x].push_back({y, c}); adj[y].push_back({x, c});}

    ll DP[32][200001] = {}; for (int i = 0; i < 32; i++) for (int j = 0; j < 200001; j++) DP[i][j] = INF;
    for (int i = 0; i < k; i++) DP[1<<i][imp[i]] = 0;

    for (int mask = 0; mask < (1<<k); mask++) {
        for (int submask = ((mask - 1) & mask); submask > 0; submask = ((submask - 1) & mask)) {
            int left = submask, right = mask ^ submask;
            if (left > right) continue;

            for (int i = 1; i <= n; i++) {
                DP[mask][i] = min(DP[mask][i], DP[left][i] + DP[right][i]);
            }
        }

        priority_queue<pi, vector<pi>, greater<pi>> pq;
        for (int i = 1; i <= n; i++) {
            if (DP[mask][i] < INF) pq.push({DP[mask][i], i});
        }

        vector<bool> vis(n+1, false);
        while (!pq.empty()) {
            int u = pq.top().second; pq.pop();

            if (vis[u]) continue;
            vis[u] = true;

            for (auto el : adj[u]) {
                ll d = DP[mask][u] + el.second;
                if (d < DP[mask][el.first]) {
                    DP[mask][el.first] = d;
                    pq.push({DP[mask][el.first], el.first});
                }
            }
        }
    }

    ll r = INF; for (int i = 1; i <= n; i++) r = min(r, DP[(1<<k)-1][i]);
    cout << r << "\n";
    return 0;
}

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