Submission #669519

#	Time	Username	Problem	Language	Result	Execution time	Memory
669519		Reb007	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	641 ms	31560 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>>> g;
struct reb{
    int v, u, w;
};
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]: g[v]) {
            if (d[v] + c < d[to]) {
                buf.erase({d[to], -to});
                d[to] = d[v] + c;
                buf.insert({d[to], -to});
            }
        }
    }
    return d;
}
vector<int> dij2(int s, set<pair<int, int>> &DAG) {
    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]: g[v]) {
            if(DAG.count({v, to}))c = 0;
            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;
    g.resize(n);
    vector<reb> eds(m);
    for (int i = 0; i < m; ++i) {
        int x, y, c;
        cin >> x >> y >> c;
        --x, --y;
        eds[i] = {x, y, c};
        g[x].push_back({y, c});
        g[y].push_back({x, c});
    }
    vector<int> ds = dij(s);
    vector<int> dt = dij(t);
    set<pair<int, int>> DAG, DAG2;

    for(auto[x, y, w]:eds){
        if(ds[x] + w + dt[y] == ds[t]){
            DAG.insert({x, y});
            DAG2.insert({y, x});
        }
        if(ds[y] + w + dt[x] == ds[t]){
            DAG.insert({y, x});
            DAG2.insert({x, y});
        }
    }
    vector<int> d = dij2(v, DAG);
    vector<int> d2 = dij2(v,DAG2);
    cout << min(d2[u], d[u]) << '\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: 0 / 24
• Subtask 4: 0 / 45