Submission #647772

#	Time	Username	Problem	Language	Result	Execution time	Memory
647772		LeonaRaging	Olympic Bus (JOI20_ho_t4)	C++14	5 / 100	1098 ms	10732 KiB

ho_t4

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

#define int long long
#define fi first
#define se second
#define ll long long
#define pb push_back
#define db(val) "[" #val " = " << (val) << "] "

const ll mod = 1e9 + 7;
const int maxn = 1e5 + 4;
const int INF = 1e10;
const int N = 205;

using T = pair<int,int>;

struct Edge {
    int u, v, w, c;
    tuple<int,int,int,int> init() {
        return {u, v, w, c};
    }
};

int n, m, d[N][N], dis[N];
Edge edges[maxn];
set<int> adj[maxn];
priority_queue<T, vector<T>, greater<T>> pq;

int dijkstra(int s, int t) {
    for (int i = 1; i <= n; i++)
        dis[i] = INF;
    dis[s] = 0; pq.push({0, s});
    while (!pq.empty()) {
        int u, d; tie(d, u) = pq.top(); pq.pop();
        if (dis[u] != d) continue;
        for (int i : adj[u]) {
            int v = edges[i].v, w = edges[i].w;
            if (dis[u] + w < dis[v]) {
                dis[v] = dis[u] + w;
                pq.push({dis[v], v});
            }
        }
    }
    return dis[t];
}

signed main()
{
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    //freopen(".INP", "r", stdin);
    //freopen(".OUT", "w", stdout);
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            if (i != j)
                d[i][j] = INF;
    for (int i = 1; i <= m; i++) {
        int u, v, w, c; cin >> u >> v >> w >> c;
        d[u][v] = min(d[u][v], w);
        edges[i] = {u, v, w, c};
        edges[i + m] = {v, u, w, c};
        adj[u].insert(i);
    }
    for (int k = 1; k <= n; k++)
        for (int u = 1; u <= n; u++)
            for (int v = 1; v <= n; v++)
                d[u][v] = min(d[u][v], d[u][k] + d[k][v]);
    int res = INF;
    int s = 1, t = n;
    res = min(res, d[s][t] + d[t][s]);
    for (int i = 1; i <= m; i++) {
        int u, v, w, c; tie(u, v, w, c) = edges[i].init();
        // int from = min(d[s][t], d[s][v] + w + d[u][t]);
        // int to = min(d[t][s], d[t][v] + w + d[u][s]);
        // if (from + to + c < res) {
            adj[u].erase(i); adj[v].insert(i + m);
            res = min(res, c + dijkstra(s, t) + dijkstra(t, s));
            adj[v].erase(i + m); adj[u].insert(i);
        // }
    }
    cout << (res == INF ? -1 : res);
}

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