Submission #445807

#	Time	Username	Problem	Language	Result	Execution time	Memory
445807		nickmet2004	Cities (BOI16_cities)	C++11	100 / 100	1244 ms	39508 KiB

cities

#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N = 2e5 + 5;
int n , k , m , A[6];
int d[6][N] , F[6][6][N] , v[N];
vector<pair<int , int>> adj[N];
void go(int a , int b , int *ans){
    priority_queue<pair<int , int> > pq;
    for(int y = 1; y <= n; ++y) {
        if(b!=0) ans[y] = d[a][y] + d[b][y], pq.push({-ans[y] , y});
        else ans[y] = 1e18;
 
    }
    if(b==0)pq.push({0 , a}) , ans[a] = 0;
    int u , w;
    while(pq.size()){
        auto T = pq.top(); pq.pop();
        u = T.second , w = -T.first;
        if(v[u])continue;
        v[u]= 1;
        int v , D;
        for(auto V : adj[u]){
            v = V.first , D = V.second;
            if(ans[v] > D + w){ans[v] = D + w; pq.push({-ans[v] , v});}
        }
    }
    memset(v , 0 , sizeof(v));
}
 main (){
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> n >> k >> m;
    for(int i = 0; i< k; ++i)cin >> A[i];
    int u , v , w;
    for(int i = 1; i<= m; ++i){
        cin >> u >> v >> w;
        adj[u].emplace_back(v , w);
        adj[v].emplace_back(u , w);
    }
    for(int i = 0; i < k; ++i) go(A[i] , 0 , d[i]);
    for(int i = 0; i< k; ++i){
        for(int j = i + 1; j < k; ++j){
            go(i , j , F[i][j]);
            //for(int x =1; x <= n; ++x)cout << i << " "<< j << " " << x << " " << F[i][j][x] << endl;
        }
    }
    /*
    for(int i = 0; i< k; ++i){
        for(int x= 1; x <= n; ++x)cout << d[i][x] << " ";
        cout << endl;
    }
    */
    if(k == 2)cout << d[0][A[1]]<<endl;
    if(k == 3)cout << F[0][1][A[2]] << endl;
    int ans = 1e18;
    if(k == 4){
        vector<int> P = {0 , 1, 2, 3};
        do{
            if(P[0] > P[1] || P[2] > P[3])continue;
            for(int i = 1; i<= n; ++i)ans = min(ans , F[P[0]][P[1]][i] + F[P[2]][P[3]][i]);
        }while(next_permutation(P.begin(), P.end()));
        cout << ans;
    }
    if(k == 5){
        vector<int> P = {0 ,1 , 2, 3 , 4};
        do{
           if(P[0] > P[1] || P[2] > P[3])continue;
           for(int i = 1; i<= n; ++i)ans = min(ans , F[P[0]][P[1]][i] + F[P[2]][P[3]][i] + d[P[4]][i]);
        }while(next_permutation(P.begin() , P.end()));
        cout << ans;
    }
}

Compilation message (stderr)

cities.cpp:30:2: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   30 |  main (){
      |  ^~~~

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