Submission #1297532

#	Time	Username	Problem	Language	Result	Execution time	Memory
1297532		fairkrash	Olympic Bus (JOI20_ho_t4)	C++20	11 / 100	15 ms	6924 KiB

ho_t4

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
ll INF = 1e18;
ll MOD = 1e9 + 7;

struct zxc {
    ll v;
    ll cost;
    ll revers;
};

struct node {
    ll a, b, c, d;
};

ll n, m;
vector<vector<zxc>> g, rg;

vector<pair<ll, ll>> dxs(ll v) {
    vector<pair<ll, ll>> dist(n, {INF, 0});
    set<pair<ll, ll>> st;
    dist[v].first = 0;
    dist[v].second = 1;
    st.insert({dist[v].first, v});
    while (!st.empty()) {
        ll u = st.begin()->second;
        st.erase(st.begin());
        for (auto to: g[u]) {
            ll cnt = to.cost + dist[u].first;
            if (dist[to.v].first > cnt) {
                st.erase({dist[to.v].first, to.v});
                dist[to.v].first = cnt;
                dist[to.v].second = dist[u].second;
                st.insert({dist[to.v].first, to.v});
            } else {
                if (dist[to.v].first == cnt) {
                    dist[to.v].second += dist[u].second;
                }
            }
        }
    }
    return dist;
}

vector<pair<ll, ll>> dxs_r(ll v) {
    vector<pair<ll, ll>> dist(n, {INF, 0});
    set<pair<ll, ll>> st;
    dist[v].first = 0;
    dist[v].second = 1;
    st.insert({dist[v].first, v});
    while (!st.empty()) {
        ll u = st.begin()->second;
        st.erase(st.begin());
        for (auto to: rg[u]) {
            ll cnt = to.cost + dist[u].first;
            if (dist[to.v].first > cnt) {
                st.erase({dist[to.v].first, to.v});
                dist[to.v].first = cnt;
                dist[to.v].second = dist[u].second;
                st.insert({dist[to.v].first, to.v});
            } else {
                if (dist[to.v].first == cnt) {
                    dist[to.v].second += dist[u].second;
                }
            }
        }
    }
    return dist;
}


vector<vector<ll>> pp;
vector<vector<ll>> dd;

vector<ll> qq;
vector<ll> used;
vector<ll> color;
ll cv = 0;

void dfs(ll v) {
    used[v] = 1;
    for (auto to: pp[v]) {
        if (used[to] == 0) {
            dfs(to);
        }
    }
    qq.push_back(v);
}

void bfs(ll v) {
    used[v] = 1;
    color[v] = cv;
    for (auto to: dd[v]) {
        if (used[to] == 0) {
            bfs(to);
        }
    }
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    cin >> n >> m;
    g.assign(n, {});
    pp.assign(n, {});
    dd.assign(n, {});
    used.assign(n, 0);
    color.assign(n, 0);
    rg.assign(n, {});
    vector<node> r(m);
    vector<ll> bad;
    for (ll i = 0; i < m; i++) {
        ll a, b, c, d;
        cin >> a >> b >> c >> d;
        a--;
        b--;
        if (c == 0) {
            pp[a].push_back(b);
            dd[b].push_back(a);
        }
        r[i] = {a, b, c, d};
    }
    for (ll i = 0; i < n; i++) {
        if (used[i] == 0) {
            dfs(i);
        }
    }
    std::reverse(qq.begin(), qq.end());
    used.assign(n, 0);
    for (ll i = 0; i < qq.size(); i++) {
        if (used[qq[i]] == 0) {
            bfs(qq[i]);
            cv++;
        }
    }
    for (ll i = 0; i < n; i++) {
        color[i] = i;
    }
    for (ll j = 0; j < m; j++) {
        r[j].a = color[r[j].a];
        r[j].b = color[r[j].b];
        ll a = r[j].a, b = r[j].b, c = r[j].c, d = r[j].d;
        if (r[j].a == r[j].b)continue;
        g[a].push_back({b, c, d});
        rg[b].push_back({a, c, d});
    }
    vector<pair<ll, ll>> dist_l_a = dxs(color[0]);
    vector<pair<ll, ll>> dist_r_a = dxs_r(color[0]);
    vector<pair<ll, ll>> dist_l_b = dxs(color[n - 1]);
    vector<pair<ll, ll>> dist_r_b = dxs_r(color[n - 1]);
    ll answer = dist_l_a[color[n - 1]].first + dist_l_b[color[0]].first;
    for (ll i = 0; i < m; i++) {
        if (r[i].a == r[i].b)continue;
        ll cnt = dist_l_a[r[i].b].first + r[i].d + r[i].c + dist_r_b[r[i].a].first + r[i].c + dist_l_b[r[i].b].first +
                 dist_r_a[r[i].a].first;
        if (dist_l_b[r[i].b].second != dist_l_b[r[i].a].second && dist_l_a[r[i].b].second != dist_l_a[r[i].a].second) {
            answer = min(answer, cnt);
        } else {
            if (answer > cnt) {
                bad.push_back(i);
            }
        }
        cnt = dist_l_a[r[i].b].first + r[i].d + r[i].c + dist_r_b[r[i].a].first + dist_l_b[color[0]].first;
        if (dist_l_b[color[0]].second != dist_l_b[r[i].a].second * dist_r_a[r[i].b].second) {
            answer = min(answer, cnt);
        } else {
            if (answer > cnt) {
                bad.push_back(i);
            }
        }
        cnt = r[i].d + r[i].c + dist_l_b[r[i].b].first +
              dist_r_a[r[i].a].first + dist_l_a[color[n - 1]].first;
        if (dist_l_a[color[n - 1]].second != dist_l_a[r[i].a].second * dist_r_b[r[i].b].second) {
            answer = min(answer, cnt);
        } else {
            if (answer > cnt) {
                bad.push_back(i);
            }
        }
    }
    if (!bad.empty()) {
        std::sort(bad.begin(), bad.end());
        bad.resize(std::unique(bad.begin(), bad.end()) - bad.begin());
    }
    for (ll i = 0; i < bad.size(); i++) {
        g.assign(n, {});
        for (ll j = 0; j < m; j++) {
            if (r[j].a == r[j].b)continue;
            ll a = r[j].a, b = r[j].b, c = r[j].c, d = r[j].d;
            if (j == bad[i]) {
                g[b].push_back({a, c, d});
                continue;
            }
            g[a].push_back({b, c, d});
        }
        vector<pair<ll, ll>> v1 = dxs(color[0]), v2 = dxs(color[n - 1]);
        answer = min(answer, v1[color[n - 1]].first + v2[color[0]].first + r[i].d);
    }
    if (answer >= INF) {
        cout << -1 << endl;
        return 0;
    }
    cout << answer;
}

• Subtask 1: 0 / 5
• Subtask 2: 11 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63