Submission #959751

#	Time	Username	Problem	Language	Result	Execution time	Memory
959751		OIaspirant2307	Olympic Bus (JOI20_ho_t4)	C++17	0 / 100	1053 ms	3156 KiB

ho_t4

#include <iostream>
#include <vector>
#include <queue>
#include <set>
#include <utility>
using namespace std;
#define int long long
#define pi pair<int, int>

const int inf = 1e17;
const int N = 203;
vector<vector<int>> cost(N, vector<int>(N, inf));
vector<vector<int>> wt(N, vector<int>(N, inf));
vector<vector<int>> dist(N, vector<int>(N, inf));
multiset<pi> g[N];
int n, m;

int dijkstra(int x, int y)
{
    vector<int> dis(n + 1, inf);
    vector<bool> vis(n + 1, 0);
    multiset<pi> ms;
    ms.insert({0, x});
    dis[x] = 0;
    while (!ms.empty())
    {
        pi p = *ms.begin();
        int v = p.second;
        if (vis[v])
        {
            continue;
        }
        vis[v] = true;
        for (auto ch : g[v])
        {
            int ch_v = ch.first;
            int ch_wt = ch.second;
            if (dis[v] + ch_wt < dis[ch_v])
            {
                dis[ch_v] = dis[v] + ch_wt;
                ms.insert({dis[ch_v], ch_v});
            }
        }
    }
    return dis[y];
}

signed main()
{
    cin >> n >> m;
    vector<pi> edges(m);
    for (int i = 0; i < m; i++)
    {
        int u, v, w, c;
        cin >> u >> v >> w >> c;
        if (g[u].size() < 2)
            g[u].insert({v, w});
        edges[i] = {u, v};
        cost[u][v] = min(cost[u][v], c);
        wt[u][v] = min(wt[u][v], w);
    }

    int ans = min(inf, dijkstra(1, n) + dijkstra(n, 1));
    for (auto p : edges)
    {
        int i = p.first;
        int j = p.second;
        g[i].erase({j, wt[i][j]});
        bool yes = g[j].count({i, wt[i][j]});
        if (yes)
        {
            g[j].insert({i, wt[i][j]});
        }
        ans = min(ans, dijkstra(1, n) + dijkstra(n, 1) + cost[i][j]);
        g[i].insert({j, wt[i][j]});
        if (yes)
        {
            g[j].erase({i, wt[i][j]});
        }
    }
    if (ans == inf)
    {
        cout << -1;
        return 0;
    }
    cout << ans << '\n';
}

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