Submission #1236496

#	Time	Username	Problem	Language	Result	Execution time	Memory
1236496		M_SH_O	Commuter Pass (JOI18_commuter_pass)	C++20	15 / 100	993 ms	49088 KiB

commuter_pass

/*#pragma GCC optimize("O3")
#pragma GCC optimization("Ofast,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")*/
#include <bits/stdc++.h>
/*#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>*/

#define ll long long
#define ll1 long long
#define ull unsigned long long
#define dou long double
#define str string
#define vll vector<ll>
#define vi vector<int>
#define pll pair<ll, ll>
#define vpll vector<pll>
#define vbool vector<bool>
#define vstr vector<str>
#define vvll vector<vll>
#define pb push_back
#define pf push_front
#define endl "\n"
#define fr first
#define se second
// #define sortcmp(a) sort(a.begin(), a.end(), cmp)
#define sort(a) sort(a.begin(), a.end())
#define reverse(a) reverse(a.begin(), a.end())
#define speed ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define INF 1000000000000000007
#define ordered_set tree<ll, null_type, less_equal<ll>, rb_tree_tag, tree_order_statistics_node_update>

using namespace std;
//using namespace __gnu_pbds;

mt19937 rng(time(0));
ll randll(ll l, ll r) {
    return uniform_int_distribution<ll>(l, r)(rng);
}

vector<vpll> g;

void dijkstra(ll n, vll& d, vector<vpll>& g) {
    set<pll> s;
    for (int i = 1; i <= n; i ++) {
        s.insert({d[i], i});
    }

    while (s.size()) {
        pll p = *s.begin();
        s.erase(s.begin());
        for (auto i : g[p.se]) {
            if (p.fr+i.se < d[i.fr]) {
                s.erase({d[i.fr], i.fr});
                d[i.fr] = p.fr+i.se;
                s.insert({d[i.fr], i.fr});
            }
        }
    }
}

vpll edge;
vbool us;

void dfs(ll v, vll& d) {
    us[v] = 1;
    for (auto i : g[v]) {
        if (us[i.fr] || d[i.fr]+i.se != d[v]) continue;
        edge.pb({i.fr, v});
        dfs(i.fr, d);
    }
}

int main(){
    speed;
    srand(time(0));

    ll n, m;
    cin >> n >> m;
    ll a, b, c, d;
    cin >> a >> b;
    cin >> c >> d;
    vector<pair<pll, ll>> ed;


    g.resize(n+7);
    for (int i = 0; i < m; i ++) {
        ll a, b, c;
        cin >> a >> b >> c;
        g[a].pb({b, c});
        g[b].pb({a, c});
        ed.pb({{a, b}, c});
    }

    vll v(n+7, INF);
    v[a] = 0;
    dijkstra(n, v, g);
    us.resize(n+7, 0);
    dfs(b, v);

    vector<vpll> g1(n+7);
    set<pll> s;
    for (auto i : edge) {
        g1[i.fr].pb({i.se, 0});
        s.insert({min(i.fr, i.se), max(i.fr, i.se)});
    }
    for (auto i : ed) {
        if (i.fr.se < i.fr.fr) swap(i.fr.fr, i.fr.se);
        if (s.find({i.fr.fr, i.fr.se}) != s.end()) continue;
        g1[i.fr.fr].pb({i.fr.se, i.se});
        g1[i.fr.se].pb({i.fr.fr, i.se});
    }

    v.clear();
    v.resize(n+7, INF);
    v[c] = 0;
    dijkstra(n, v, g1);
    dijkstra(n, v, g);

    ll minl = v[d];


    g1.clear();
    g1.resize(n+7);

    for (auto i : edge) {
        g1[i.se].pb({i.fr, 0});
    }
    for (auto i : ed) {
        if (i.fr.se < i.fr.fr) swap(i.fr.fr, i.fr.se);
        if (s.find({i.fr.fr, i.fr.se}) != s.end()) continue;
        g1[i.fr.fr].pb({i.fr.se, i.se});
        g1[i.fr.se].pb({i.fr.fr, i.se});
    }
    v.clear();
    v.resize(n+7, INF);
    v[c] = 0;
    dijkstra(n, v, g1);
    dijkstra(n, v, g);
    minl = min(minl, v[d]);

    cout << minl << endl;
}

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