Submission #833392

#	Time	Username	Problem	Language	Result	Execution time	Memory
833392		vjudge1	Commuter Pass (JOI18_commuter_pass)	C++17	0 / 100	69 ms	8884 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
#define ll long long

int n, m;
int s, t;
int u, v;
vector<vector<pair<int,int>>> edg;
bool vis[100005];
ll distS[100005];
ll distT[100005];
ll distV[100005];

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> m;
    cin >> s >> t;
    cin >> u >> v;
    edg.resize(n+5);
    for (int i = 0; i < n; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        edg[a].push_back({b,c});
        edg[b].push_back({a,c});
    }

    priority_queue<pair<int,int>> q;
    q.push({0,s});
    for (int i = 0; i <= n; i++) distS[i] = 1e18, vis[i] = 0;
    distS[s] = 0;
    while (!q.empty()) {
        int f = q.top().second;
        q.pop();
        if (vis[f]) continue;
        vis[f] = 1;
        for (auto &[i,j] : edg[f]) {
            if (!vis[i] && distS[i] > (ll) distS[f] + j) {
                distS[i] = (ll) distS[f] + j;
                q.push({-distS[i], i});
            }
        }
    }

    q.push({0,t});
    for (int i = 0; i <= n; i++) distT[i] = 1e18, vis[i] = 0;
    distT[t] = 0;
    while (!q.empty()) {
        int f = q.top().second;
        q.pop();
        if (vis[f]) continue;
        vis[f] = 1;
        for (auto &[i,j] : edg[f]) {
            if (!vis[i] && distT[i] > (ll) distT[f] + j) {
                distT[i] = (ll) distT[f] + j;
                q.push({-distT[i], i});
            }
        }
    }

    q.push({0,v});
    for (int i = 0; i <= n; i++) distV[i] = 1e18, vis[i] = 0;
    distV[v] = 0;
    while (!q.empty()) {
        int f = q.top().second;
        q.pop();
        if (vis[f]) continue;
        vis[f] = 1;
        for (auto &[i,j] : edg[f]) {
            if (!vis[i] && distV[i] > (ll) distV[f] + j) {
                distV[i] = (ll) distV[f] + j;
                q.push({-distV[i], i});
            }
        }
    }

    ll ans = 1e18;
    for (int i = 1; i <= n; i++) {
        if (distS[t] == distS[i] + distT[i]) {
            ans = min(ans, distV[i]);
        }
    }
    cout << ans << '\n';

    //cerr << "S: "; for (int i = 1; i <= n; i++) { cerr << distS[i] << " \n" [i == n]; }
    //cerr << "T: "; for (int i = 1; i <= n; i++) { cerr << distT[i] << " \n" [i == n]; }
    //cerr << "V: "; for (int i = 1; i <= n; i++) { cerr << distV[i] << " \n" [i == n]; }

    return 0;
}

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