Submission #595326

#	Time	Username	Problem	Language	Result	Execution time	Memory
595326		Wael	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	470 ms	71068 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int long long
//#define endl '\n'
#define F first
#define S second
int const M = 1e6 + 10 , N = 1e3 + 10 , mod = 1e9 + 7;
ll T , n , m , k , cost , x , y , s , t , u , v , type , ans = 1e18 , dis[6][M] , cnt[M] , on[M] , U[M] , V[M];
int dx[] = {1 , -1 , 0 , 0} , dy[] = {0 , 0 , 1 , -1};
priority_queue<pair<ll , ll> , vector<pair<ll , ll>> , greater<pair<ll , ll>>>q;
vector<pair<ll , ll>>adj[M];
vector<ll>graph[M] , top;
bool vis[M];

inline void Dijkstra(int start) {
   q.push({0 , start});
   while(q.size()) {
    int node = q.top().S;
    int cost = q.top().F;
    q.pop();
    if(dis[type][node] || node == start && cost) continue;
    dis[type][node] = cost;
    for(auto next : adj[node]) q.push({cost + next.S , next.F});
   }
}


inline void GetPath(int node) {
   vis[node] = 1;
   for(auto next : adj[node]) {
    int kid = next.F;
    if(dis[3][kid] + dis[4][kid] != dis[3][t] || vis[kid]) continue;
    graph[node].push_back(kid);
    graph[kid].push_back(node);
    ++cnt[node] , ++cnt[kid];
    on[node] = 1; on[kid] = 1;
    GetPath(kid);
   }
}

inline void Bfs() {
   queue<ll>Q;
   Q.push(s);
   while(Q.size()) {
    int node = Q.front();
    Q.pop();
    top.push_back(node);
    for(auto next : graph[node]) {
        --cnt[next];
        if(cnt[next] == 1) Q.push(next);
    }
   }
   top.push_back(t);
}

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

    cin >> n >> m >> s >> t >> u >> v;
    for(int i = 1 ; i <= m ; ++i) {
        cin >> x >> y >> cost;
        adj[x].push_back({y , cost});
        adj[y].push_back({x , cost});
    }
    type = 1; Dijkstra(u);
    type = 2; Dijkstra(v);
    type = 3; Dijkstra(s);
    type = 4; Dijkstra(t);
    GetPath(s);
    Bfs();
    for(int i = 1 ; i <= n ; ++i) U[i] = V[i] = 1e18;
    ans = dis[1][v];
    for(auto node : top) {
        ans = min(ans , dis[1][node] + V[node]);
        ans = min(ans , dis[2][node] + U[node]);
        U[node] = min(U[node] , dis[1][node]);
        V[node] = min(V[node] , dis[2][node]);
        for(auto next : graph[node]) U[next] = min(U[next] , U[node]) , V[next] = min(V[next] , V[node]);
    }
    cout << ans << endl;
    return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'void Dijkstra(long long int)':
commuter_pass.cpp:22:41: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   22 |     if(dis[type][node] || node == start && cost) continue;
      |                           ~~~~~~~~~~~~~~^~~~~~~
commuter_pass.cpp: At global scope:
commuter_pass.cpp:57:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   57 | main() {
      | ^~~~

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