Submission #646245

#	Time	Username	Problem	Language	Result	Execution time	Memory
646245		fatemetmhr	Cities (BOI16_cities)	C++17	29 / 100	6044 ms	26916 KiB

cities

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define all(x)  x.begin(), x.end()
#define pb      push_back
#define fi      first
#define se      second
#define mp      make_pair

const int maxn5 = 2e5 + 10;
const int maxn3 = 1e3 + 10;
const ll  inf   = 1e18;

int n;
vector <int> imp;
vector <pair<int, ll>> adj[maxn5];
set <pair<ll, int>> av;
ll dis[5][maxn5], dis2[maxn3][maxn3];

inline void dij(int r, int id){
    av.clear();
    for(int i = 0; i < n; i++)
        dis[id][i] = inf;
    dis[id][r] = 0;
    for(int i = 0; i < n; i++)
        av.insert({dis[id][i], i});
    while(av.size()){
        int v = av.begin() -> se;
        av.erase(av.begin());
        for(auto p : adj[v]){
            int u = p.fi;
            ll w = p.se;
            if(dis[id][u] < dis[id][v] + w)
                continue;
            av.erase({dis[id][u], u});
            dis[id][u] = dis[id][v] + w;
            av.insert({dis[id][u], u});
        }
    }
    return;
}

inline void dij2(int r, int id){
    av.clear();
    for(int i = 0; i < n; i++)
        dis2[id][i] = inf;
    dis2[id][r] = 0;
    for(int i = 0; i < n; i++)
        av.insert({dis2[id][i], i});
    while(av.size()){
        int v = av.begin() -> se;
        av.erase(av.begin());
        for(auto p : adj[v]){
            int u = p.fi;
            ll w = p.se;
            if(dis2[id][u] < dis2[id][v] + w)
                continue;
            av.erase({dis2[id][u], u});
            dis2[id][u] = dis2[id][v] + w;
            av.insert({dis2[id][u], u});
        }
    }
    return;
}

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

    int k, m; cin >> n >> k >> m;
    for(int i = 0; i < k; i++){
        int a; cin >> a; a--;
        imp.pb(a);
    }
    for(int i = 0; i < m; i++){
        int a, b, c; cin >> a >> b >> c;
        a--; b--;
        adj[a].pb({b, c});
        adj[b].pb({a, c});
    }

    for(int i = 0; i < k; i++)
        dij(imp[i], i);

    if(k == 2){
        cout << dis[0][imp[1]] << endl;
        return 0;
    }

    if(k == 3){
        ll ans = dis[0][imp[1]] + dis[1][imp[2]];
        for(int i = 0; i < n; i++)
            ans = min(ans, dis[0][i] + dis[1][i] + dis[2][i]);
        return cout << ans << endl, 0;
    }

    for(int i = 0; i < n; i++)
        dij2(i, i);

    ll ans = inf;
    //cout << "check " << endl;
    int a0 = imp[0], a1 = imp[1], a2 = imp[2], a3 = imp[3];
    for(int i = 0; i < n; i++) for(int j = 0; j < n; j++){
        ans = min(ans, dis2[a0][i] + dis2[a1][i] + dis2[a2][j] + dis2[a3][j] + dis2[i][j]);
        ans = min(ans, dis2[a0][i] + dis2[a1][j] + dis2[a2][i] + dis2[a3][j] + dis2[i][j]);
        ans = min(ans, dis2[a0][i] + dis2[a1][j] + dis2[a2][j] + dis2[a3][i] + dis2[i][j]);
        //cout << i << ' ' << j << ' ' << ans << endl;
    }
    //for(auto u : imp)
    //    cout << u << ' ' << dis2[u][0] << endl;
    //cout << dis2[0][1] << ' ' << dis2[0][2] << ' ' << dis2[0][3] << ' ' << dis2[0][4] << ' ' << dis2[0][5] << endl;
    cout << ans << endl;
}

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