Submission #940112

#	Time	Username	Problem	Language	Result	Execution time	Memory
940112		Darren0724	Cities (BOI16_cities)	C++17	15 / 100	157 ms	64596 KiB

cities

#include <bits/stdc++.h>
using namespace std;
#define LCBorz ios_base::sync_with_stdio(false); cin.tie(0);
#define int long long 
#define all(x) x.begin(), x.end()
#define endl '\n'
const int N=2005;
const int INF=1e18;
int n,k,m;
vector<int> s;
vector<pair<int,int>> adj[N];
vector dis(5,vector<int>(N,INF));
vector dis1(N,vector<int>(N,INF));
void dijk(int s,vector<int> &dis){
    dis[s]=0;
    priority_queue<pair<int,int>> pq;
    pq.push({0,s});
    while(pq.size()){
        auto [dis1,a]=pq.top();
        pq.pop();
        dis1=-dis1;
        if(dis1!=dis[a])continue;
        for(auto [c,d]:adj[a]){
            int cost=dis1+d;
            if(dis[c]>cost){
                dis[c]=cost;
                pq.push({-dis[c],c});
            }
        }
    }
}
int32_t main() {
    LCBorz;
    cin>>n>>k>>m;    
    for(int i=0;i<k;i++){
        int p;cin>>p;
        s.push_back(p);
    }
    for(int i=0;i<m;i++){
        int a,b,c;cin>>a>>b>>c;
        adj[a].push_back({b,c});
        adj[b].push_back({a,c});
    }
    for(int i=0;i<k;i++){
        dijk(s[i],dis[i]);
    }
    for(int i=1;i<=n;i++){
        dijk(i,dis1[i]);
    }
    int ans=INF;
    for(int i=1;i<=n;i++){
        int cost=0;
        for(int j=0;j<k;j++){
            cost+=dis[j][i];
        }
        ans=min(ans,cost);
    }
    for(int i=1;i<=n;i++){
        for(int j=i+1;j<=n;j++){
            int cost=dis1[i][j];
            for(int p=0;p<k;p++){
                cost+=min(dis[p][i],dis[p][j]);
            }
            ans=min(ans,cost);
        }
    }
    cout<<ans<<endl;

    return 0;
}

• Subtask 1: 0 / 22
• Subtask 2: 0 / 14
• Subtask 3: 15 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 26