Submission #670357

#	Time	Username	Problem	Language	Result	Execution time	Memory
670357		Reb007	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	527 ms	31936 KiB

commuter_pass

// clang-format off
#include <bits/stdc++.h>

using namespace std;
mt19937 rnd(time(0));
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("fast-math")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")
#define int long long
#define ll long long
#define ld long double
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
const long long INF = 20000000000000000;
const int inf = 1000000010;
const int maxn = 262144;
const int mxlg = 20;
const double eps = 1e-13;
int mod = 1e9 + 9;
const int C = 340;
vector<vector<pair<int, int>>>
        eds;
vector<vector<int>> g2;
int n;

vector<int> dij(int s) {
    vector<int> d(n, INF);
    d[s] = 0;
    set<pair<int, int>> buf;
    buf.insert({0, s});
    while (!buf.empty()) {
        int v = buf.begin()->second;
        buf.erase(buf.begin());
        for (auto [to, c]: eds[v]) {
            if (d[v] + c < d[to]) {
                buf.erase({d[to], to});
                d[to] = d[v] + c;
                buf.insert({d[to], to});
            }
        }
    }
    return d;
}

void solve() {
    int m, s, t, v, u;
    cin >> n >> m >> s >> t >> v >> u;
    --s, --t, --v, --u;
    eds.resize(n);
    for (int i = 0; i < m; ++i) {
        int x, y, c;
        cin >> x >> y >> c;
        --x, --y;
        eds[x].push_back({y, c});
        eds[y].push_back({x, c});
    }
    vector<int> st = dij(s);
    vector<int> ts = dij(t);
    vector<bool> dag(n);
    g2.resize(n);
    dag[s] = dag[t] = 1;
    for (int i = 0; i < n; ++i) {
        for (auto [to, w]: eds[i]) {
            if (st[i] + w + ts[to] == st[t]) {
                dag[i] = dag[to] = 1;
                g2[i].push_back(to);
            }
        }
    }
    vector<int> dv = dij(v);
    vector<int> du = dij(u);
    int ans = dv[u];
    set<pair<int, int>> buf;
    vector<int> cost = dv;
    for (int i = 0; i < n; ++i) {
        if (dag[i]) {
            buf.insert({dv[i], i});
        }
    }
    while (!buf.empty()) {
        int cur = buf.begin()->second;
        buf.erase(buf.begin());
        ans = min(ans, cost[cur] + du[cur]);
        for (int to: g2[cur]) {
            if (cost[cur] < cost[to]) {
                buf.erase({cost[to], to});
                cost[to] = cost[cur];
                buf.insert({cost[to], to});
            }
        }
    }
    cost = du;
    for (int i = 0; i < n; ++i) {
        if (dag[i]) {
            buf.insert({du[i], i});
        }
    }
    while (!buf.empty()) {
        int cur = buf.begin()->second;
        buf.erase(buf.begin());
        ans = min(ans, cost[cur] + dv[cur]);
        for (int to: g2[cur]) {
            if (cost[cur] < cost[to]) {
                buf.erase({cost[to], to});
                cost[to] = cost[cur];
                buf.insert({cost[to], to});
            }
        }
    }
    cout << ans << "\n";
}

signed main() {
//    freopen("kthzero.in", "r", stdin);
//    freopen("kthzero.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int __ = 1;
//    cin >> __;
    while (__--)
        solve();
    return 0;
}

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