Submission #1311624

#	Time	Username	Problem	Language	Result	Execution time	Memory
1311624		filip1111	Commuter Pass (JOI18_commuter_pass)	C++20	31 / 100	1565 ms	87624 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = long long;
const int N = 1e5 + 99;
vector<pair<int,ll>>tab[N];
const ll inf = 1e18;
ll odl[N];

ll dijkstra(int a, int b, int n){
    for(int i = 0; i < n+ 9; ++i)odl[i] = inf;
    priority_queue<pair<ll,int>, vector<pair<ll,int>>, greater<pair<ll,int>>> pq;
    pq.push({0,a});
    while(!pq.empty()){
        auto[x,v] = pq.top();
        pq.pop();
        if(odl[v] <= x)continue;
        odl[v] = x;
        for(auto [u,y] : tab[v]){
            pq.push({x+y,u});
        }
    }
    return odl[b];
}
ll odl2[N][3];

ll dijkstra2(int a,int b,int n){
    for(int i = 0; i < n + 9; i++){
        odl2[i][0] = odl2[i][1] = odl2[i][2] = inf;
    }
    priority_queue<pair<ll,pair<int,int>>, vector<pair<ll,pair<int,int>>>, greater<pair<ll,pair<int,int>>>> pq;
    pq.push({0,{a,0}});
    while(!pq.empty()){
        auto[x, p1] = pq.top();
        pq.pop();
        auto[v, l] = p1;
        if(odl2[v][l] <= x)continue;
        odl2[v][l] = x;
        for(auto [u,w] : tab[v]){
            if(l == 0){
                if(w == 0)pq.push({x,{u,1}});
                else pq.push({x+w,{u,0}});
            }
            else if(l == 1){
                if(w == 0)pq.push({x,{u,1}});
                else pq.push({x+w,{u,2}});
            }
            else if(l == 2){
                if(w != 0){
                    pq.push({x+w,{u,2}});
                }
            }
        }
    }
    return min(min(odl2[b][1],odl2[b][0]),odl2[b][2]);
}
bool vis[N];
map<pair<int,int>,bool>M;
map<pair<int,int>,int>Star;
void dfs(int v, ll x){
    assert(odl[v] == x);
    if(x == 0)return;
    if(vis[v])return;
    vis[v] = 1;
    ll mini = inf;
    for(auto [u,y] : tab[v]){
        mini = min(mini, odl[u] + y);
    }
    for(auto [u, y] : tab[v]){
        if(mini == odl[u] + y){
            dfs(u,x - y);
            M[{u,v}]=1;
            // M[{v,u}]=1;
        }
    }
}
int main(){
    int n, m;
    cin >> n >> m;
    int S,T, U, V;
    cin >> S >> T >> U >> V;
    for(int i = 0; i < m; i++){
        int a, b, c;
        cin >> a >> b >> c;
        tab[a].push_back({b,c});
        Star[{a,b}] = c;
        Star[{b,a}] = c;
        tab[b].push_back({a,c});
    }
    ll oo = dijkstra(S,T,n);
    dfs(T,oo);
    for(int i = 1; i <= n; i++){
        for(auto &[v,x] : tab[i]){
            if(M[{i,v}])x = 0;
            else x = Star[{i,v}];
        }
    }
    ll ooo =  max(dijkstra2(U,V,n),dijkstra(U,V,n));
    for(int i = 1; i <= n; i++){
        for(auto &[v,x] : tab[i]){
            if(M[{v,i}])x = 0;
            else x = Star[{i,v}];
        }
    }
    ll oooo = max(dijkstra2(U,V,n),dijkstra(U,V,n));;
    cout << min(ooo,oooo) << endl;
    
} 

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45