Submission #1245824

#	Time	Username	Problem	Language	Result	Execution time	Memory
1245824		sheyer	Cities (BOI16_cities)	C++20	100 / 100	1585 ms	40652 KiB

cities

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e18;
int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    int n, k, m;
    cin >> n >> k >> m;
    vector<int> t(k);
    for(int i = 0; i < k; i++) cin >> t[i];
    vector<vector<pair<int,int>>> adj(n+1);
    for(int i = 0; i < m; i++){
        int u, v, w;
        cin >> u >> v >> w;
        adj[u].emplace_back(v, w);
        adj[v].emplace_back(u, w);
    }
    int full = (1 << k);
    vector<vector<ll>> dp(full, vector<ll>(n+1, INF));
    for(int i = 0; i < k; i++) dp[1<<i][t[i]] = 0;
    for(int mask = 1; mask < full; mask++){
        if((mask & (mask - 1))){
            for(int sub = (mask - 1) & mask; sub; sub = (sub - 1) & mask){
                int other = mask ^ sub;
                for(int v = 1; v <= n; v++){
                    ll c = dp[sub][v] + dp[other][v];
                    if(c < dp[mask][v]) dp[mask][v] = c;
                }
            }
        }
        // Dijkstra
        priority_queue<pair<ll,int>, vector<pair<ll,int>>, greater<pair<ll,int>>> pq;
        for(int v = 1; v <= n; v++){
            if(dp[mask][v] < INF) pq.emplace(dp[mask][v], v);
        }
        while(!pq.empty()){
            auto [d, u] = pq.top(); pq.pop();
            if(d != dp[mask][u]) continue;
            for(auto &e: adj[u]){
                int v = e.first;
                ll nd = d + e.second;
                if(nd < dp[mask][v]){
                    dp[mask][v] = nd;
                    pq.emplace(nd, v);
                }
            }
        }
    }
    ll ans = INF;
    for(int v = 1; v <= n; v++) ans = min(ans, dp[full-1][v]);
    cout << ans;
    return 0;
}

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