Submission #683442

#	Time	Username	Problem	Language	Result	Execution time	Memory
683442		yogesh_sane	Commuter Pass (JOI18_commuter_pass)	C++17	0 / 100	2079 ms	17272 KiB

commuter_pass

#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <climits>
using namespace std;
int n, m, s, t, u, v;
vector<vector<pair<int, int>>>adj;
void dijkstras(int start, int end, vector<long long> &dist, vector<bool> &path){
    priority_queue<pair<long long, int>> q;
    vector<bool> visited(n+1);
    vector<vector<int>>parents(n+1);
    dist[start] = 0;
    q.push({0,start});
    while(!q.empty()){
        int node = q.top().second;
        q.pop();
        if(visited[node])
            continue;
        visited[node] = true;
        for(auto edge : adj[node]){
            int next = edge.first;
            int weight = edge.second;
            if(dist[node] + weight < dist[next]){
                dist[next] = dist[node] + weight;
                parents[next].clear();
                parents[next].push_back(node);
                q.push({-dist[next],next});
            }else if(dist[node] + weight == dist[next]){
                parents[next].push_back(node);
            }
        }
    }
    stack<int>stk;
    stk.push(end);
    while(!stk.empty()){
        int node = stk.top();
        stk.pop();
        path[node] = true;
        for(auto p : parents[node])
            stk.push(p);
    }
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m >> s >> t >> u >> v;
    adj = vector<vector<pair<int, int>>>(n+1);
    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});
    }
    vector<long long> distS(n+1, LONG_LONG_MAX), distV(n+1, LONG_LONG_MAX);
    vector<bool> pathS(n+1), pathV(n+1);
    dijkstras(s,t,distS,pathS);
    dijkstras(v,u,distV,pathV);
    long long ans = distV[u];
    for(int i = 1; i <= n; i++){
        if(pathS[i])
            ans = min(ans, distV[i]);
    }
    cout << ans << '\n';
    return 0;
}

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