Submission #964323

#	Time	Username	Problem	Language	Result	Execution time	Memory
964323		Akshat369	Olympic Bus (JOI20_ho_t4)	C++17	0 / 100	30 ms	6492 KiB

ho_t4

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

#define int long long
#define INF LLONG_MAX
#define endl '\n'
const int mod = 1000 * 1000 * 1000 + 7;
const int N = 205;
#define f first
#define s second
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define rrep(i, a, b) for(int i = (a); i > (b); i--)
#define vi vector<int>
#define pii pair<int, int>
#define all(x) (x).begin(), (x).end()

mt19937_64 RNG(chrono::steady_clock::now().time_since_epoch().count());

struct node {
    int u, v, c, d;
};

multiset<pair<int, int>> graph[N];

vector<int> dijkstra(int src) {
    vector<int> dist(N, INF);
    vector<int> vis(N, false);

    dist[src] = 0;
    priority_queue<pii, vector<pii>, greater<pii>> pq;
    pq.push({0, src});

    while (!pq.empty()) {
        auto uu = pq.top();
        pq.pop();
        int u = uu.second;
        if (vis[u]) continue;
        vis[u] = true;

        for (auto& vv : graph[u]) {
            int v = vv.first;
            int weight = vv.second;
            if (dist[v] > dist[u] + weight) {
                dist[v] = dist[u] + weight;
                pq.push({dist[v], v});
            }
        }
    }
    return dist;
}

void solve() {
    int n, m;
    cin >> n >> m;
    vector<node> edges(m);
    for (int i = 0; i < m; ++i) {
        cin >> edges[i].u >> edges[i].v >> edges[i].c >> edges[i].d;
        graph[edges[i].u].insert({edges[i].v, edges[i].c});
    }

    vector<vector<int>> dist(n + 1, vector<int>(n + 1, INF));
    for (auto& e : edges) {
        dist[e.u][e.v] = min(dist[e.u][e.v], e.c);
    }

    for (int k = 1; k <= n; ++k) {
        for (int i = 1; i <= n; ++i) {
            for (int j = 1; j <= n; ++j) {
                dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
            }
        }
    }

    int ans = INF;
    for (auto& e : edges) {
        int temp1 = min(dist[1][e.v] + dist[e.u][n] + e.c, dist[1][n]);
        int temp2 = min(dist[n][e.u] + dist[e.v][1] + e.c, dist[n][1]);
        if (temp1 + temp2 + e.d < ans) {
            graph[e.u].erase(graph[e.u].find({e.v, e.c}));
            graph[e.v].insert({e.u, e.c});

            auto dis1 = dijkstra(1);
            auto dis2 = dijkstra(n);
            ans = min(ans, dis1[n] + dis2[1] + e.d);

            graph[e.v].erase(graph[e.v].find({e.u, e.c}));
            graph[e.u].insert({e.v, e.c});
        }
    }

    if (ans >= INF) cout << -1 << endl;
    else cout << ans << endl;
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    // cin >> t;
    for (int i = 1; i <= t; i++) {
        // cout << "Case #" << i << ": ";
        solve();
    }

    return 0;
}

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