Submission #681769

#	Time	Username	Problem	Language	Result	Execution time	Memory
681769		zeroesandones	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	317 ms	25232 KiB

commuter_pass

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

typedef long long ll;
typedef long double ld;
typedef vector<ll> vi;
typedef pair<ll, ll> pi;

#define FOR(i, j, k) for (ll i = j; i < (ll) k; ++i)
#define FORD(i, j, k) for (ll i = j; i >= (ll) k; --i)
#define nl "\n"
#define sp " "

#define all(x) (x).begin(), (x).end()
#define sc second
#define fr first
#define pb emplace_back

struct edge {
    ll b, w;
    ll id;
};

const ll mxN = 1e5 + 5;
ll n, m;
vector<edge> adj[mxN];
vi distU, distV;

vi djik(ll x) {
    vi dist(n + 1, 1e15);
    bool vis[n + 1] = {};
    priority_queue<pi> pq;
    dist[x] = 0;
    pq.emplace(0, x);
    while(!pq.empty()) {
        ll u = pq.top().sc;
        pq.pop();
        if(vis[u]) continue;
        vis[u] = true;

        for(auto [v, w, id] : adj[u]) {
            if(dist[v] > dist[u] + w) {
                dist[v] = dist[u] + w;
                pq.emplace(-dist[v], v);
            }
        }
    }

    return dist;
}

ll solve(ll x, ll y) {
    ll dpU[n + 1], dpV[n + 1];
    fill(dpU, dpU + n + 1, 1e15);
    fill(dpV, dpV + n + 1, 1e15);

    vi dist(n + 1, 1e15);
    ll from[n + 1] = {};
    bool vis[n + 1] = {};
    priority_queue<pi> pq;
    dist[x] = 0;
    from[x] = 0;
    pq.emplace(0, x);
    while(!pq.empty()) {
        ll u = pq.top().sc;
        ll d = -pq.top().fr;
        pq.pop();
        if(!vis[u]) {
            vis[u] = true;
            dpU[u] = min(distU[u], dpU[from[u]]);
            dpV[u] = min(distV[u], dpV[from[u]]);
            for(auto [v, w, id] : adj[u]) {
                if(dist[v] > dist[u] + w) {
                    dist[v] = dist[u] + w;
                    from[v] = u;
                    pq.emplace(-dist[v], v);
                }
            }
        } else if(d == dist[u]) {
            if(min(distU[u], dpU[from[u]]) + min(distV[u], dpV[from[u]]) <= dpU[u] + dpV[u]) {
                dpU[u] = min(distU[u], dpU[from[u]]);
                dpV[u] = min(distV[u], dpV[from[u]]);
            }
        }
    }

    return dpU[y] + dpV[y];
}

void solve()
{
    cin >> n >> m;

    ll s, t;
    cin >> s >> t;

    ll u, v;
    cin >> u >> v;

    FOR(i, 0, m) {
        ll a, b, c;
        cin >> a >> b >> c;
        edge curr;
        curr.b = b;
        curr.w = c;
        curr.id = i;
        adj[a].pb(curr);
        curr.b = a;
        adj[b].pb(curr);
    }

    distU = djik(u);
    distV = djik(v);

    ll ans = distU[v];

    ans = min(ans, solve(s, t));
    ans = min(ans, solve(t, s));

    cout << ans << nl;
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    ll t = 1;
    // cin >> t;
    while (t--)
    {
        solve();
    }
}

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