Submission #1047647

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047647		inkvizytor	Commuter Pass (JOI18_commuter_pass)	C++17	0 / 100	115 ms	22472 KiB

commuter_pass

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

#define ll long long
#define pli pair<ll, int>
#define fi first 
#define se second

ll MAX = 1e18;

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m, s, t, u, v;
    cin >> n >> m >> s >> t >> u >> v;
    vector<vector<pli>> g (n+1);
    for (int i = 0; i < m; i++) {
        int a, b;
        ll c;
        cin >> a >> b >> c;
        g[a].push_back({c, b});
        g[b].push_back({c, a});
    }
    vector<ll> lu(n+1, -1), lv(n+1, -1), ls(n+1, -1);
    lu[u] = 0; lv[v] = 0; ls[s] = 0;
    priority_queue<pli, vector<pli>, greater<pli>> pq;
    pq.push({0, u});
    while (!pq.empty()) {
        pli x = pq.top();
        pq.pop();
        for (pli y : g[x.se]) {
            if (lu[y.se] == -1) {
                lu[y.se] = x.fi+y.fi;
                pq.push({lu[y.se], y.se});
            }
        }
    }
    pq.push({0, v});
    while (!pq.empty()) {
        pli x = pq.top();
        pq.pop();
        for (pli y : g[x.se]) {
            if (lv[y.se] == -1) {
                lv[y.se] = x.fi+y.fi;
                pq.push({lv[y.se], y.se});
            }
        }
    }
    vector<ll> mu(n+1, MAX), mv(n+1, MAX);
    mu[s] = lu[s];
    mv[s] = lv[s]; 
    pq.push({0, s});
    vector<ll> score(n+1, MAX);
    while (!pq.empty()) {
        pli x = pq.top();
        pq.pop();
        score[x.se] = min(score[x.se], min(mv[x.se]+lu[x.se], mu[x.se]+lv[x.se]));
        for (pli y : g[x.se]) {
            if (ls[y.se] == -1) {
                ls[y.se] = x.fi+y.fi;
                mu[y.se] = min(mu[x.se], lu[y.se]);
                mv[y.se] = min(mv[x.se], lv[y.se]);
                score[y.se] = score[x.se];
                pq.push({ls[y.se], y.se});
            }
            else if (x.fi+y.fi == ls[y.se]) {
                mu[y.se] = min(mu[x.se], mu[y.se]);
                mv[y.se] = min(mv[x.se], mv[y.se]);
                score[y.se] = min(score[y.se], score[x.se]);
            }
        }
    }
    cout << min(score[t], lu[v]) << '\n';
}

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