Submission #930290

#	Time	Username	Problem	Language	Result	Execution time	Memory
930290		fskarica	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	659 ms	262144 KiB

commuter_pass

#include <bits/stdc++.h>

using namespace std;

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

const ll MAX = 2e5 + 10;
ll n, m;
ll s, t;
ll u, v;
ll x, y, w, w2;
vector <pii> veze[MAX];
ll dis[MAX][2];
ll sol[MAX][2];
ll arr[MAX];
ll trm[MAX];
queue <ll> q;

void distance(ll root, ll o) {
    priority_queue <pii> q;

    q.push({0, root});
    dis[root][o] = 0;

    while (!q.empty()) {
        w = -q.top().fi;
        x = q.top().se;
        q.pop();

        if (dis[x][o] != w) continue;

        for (auto e : veze[x]) {
            y = e.fi;
            w2 = w + e.se;

            if (dis[y][o] != -1 && dis[y][o] <= w2) continue;

            dis[y][o] = w2;
            q.push({-w2, y});
        }
    }
}

void bfs(ll root) {
    priority_queue <pii> q;

    q.push({0, root});
    arr[root] = 0;

    while (!q.empty()) {
        w = -q.top().fi;
        x = q.top().se;
        q.pop();

        if (arr[x] != w) continue;

        for (auto e : veze[x]) {
            y = e.fi;
            w2 = w + e.se;

            if (arr[y] != -1 && arr[y] <= w2) continue;

            arr[y] = w2;
            q.push({-w2, y});
        }
    }
}

void tramvaj(ll root) {
    queue <ll> q;

    q.push(root);
    trm[root] = 1;

    while (!q.empty()) {
        x = q.front();
        q.pop();

        for (auto e : veze[x]) {
            if (arr[e.fi] + e.se != arr[x]) continue;

            trm[e.fi] = 1;
            q.push(e.fi);
        }
    }
}

int main() {
    cin >> n >> m;
    cin >> s >> t >> u >> v;

    memset(dis, -1, sizeof(dis));
    memset(arr, -1, sizeof(arr));

    for (ll i = 0; i < m; i++) {
        cin >> x >> y >> w;

        veze[x].push_back({y, w});
        veze[y].push_back({x, w});
    }

    distance(u, 0);
    distance(v, 1);

    bfs(s);
    tramvaj(t);

    for (ll i = 1; i <= n; i++) {
        if (!trm[i]) continue;

        sol[i][0] = dis[i][0];
        sol[i][1] = dis[i][1];
    }

    q.push(s);
    while (!q.empty()) {
        x = q.front();
        q.pop();

        for (auto e : veze[x]) {
            if (!trm[e.fi]) continue;
            if (arr[e.fi] != arr[x] + 1) continue;

            q.push(e.fi);
            sol[e.fi][0] = min(sol[e.fi][0], sol[x][0]);
        }
    }

    q.push(t);
    while (!q.empty()) {
        x = q.front();
        q.pop();

        for (auto e : veze[x]) {
            if (!trm[e.fi]) continue;
            if (arr[e.fi] + 1 != arr[x]) continue;

            q.push(e.fi);
            sol[e.fi][1] = min(sol[e.fi][1], sol[x][1]);
        }
    }

    ll rez = dis[v][0];
    for (ll i = 1; i <= n; i++) {
        if (!trm[i]) continue;

        rez = min(rez, sol[i][0] + sol[i][1]);
    }

    cout << rez << "\n";

//    cout << "U dis[" << u << "] = "; for (ll i = 1; i <= n; i++) cout << dis[i][0] << " "; cout << "\n";
//    cout << "V dis[" << v << "] = "; for (ll i = 1; i <= n; i++) cout << dis[i][1] << " "; cout << "\n";
//    cout << "\n";
//
//
//    cout << "bfs -> "; for (ll i = 1; i <= n; i++) cout << arr[i] << " "; cout << "\n";
//    cout << "trm -> "; for (ll i = 1; i <= n; i++) cout << trm[i] << " "; cout << "\n";

    return 0;
}

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