Submission #708493

#	Time	Username	Problem	Language	Result	Execution time	Memory
708493		finn__	Robot (JOI21_ho_t4)	C++17	0 / 100	3051 ms	54024 KiB

Main

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

struct Edge
{
    size_t v, c, p;
};

constexpr size_t N = 100000;

vector<Edge> g[N];
map<size_t, size_t> ccost[N], f[N];
size_t d[N];

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

    size_t n, m;
    cin >> n >> m;

    for (size_t i = 0; i < m; i++)
    {
        size_t u, v, c, p;
        cin >> u >> v >> c >> p;
        g[u - 1].push_back({v - 1, c, p});
        g[v - 1].push_back({u - 1, c, p});
        ccost[u - 1][c] += p;
        ccost[v - 1][c] += p;
    }

    auto compare_state = [](tuple<size_t, size_t, size_t> const &a,
                            tuple<size_t, size_t, size_t> const &b)
    { return get<1>(a) > get<1>(b); };

    priority_queue<tuple<size_t, size_t, size_t>,
                   vector<tuple<size_t, size_t, size_t>>, decltype(compare_state)>
        q(compare_state);

    fill(d + 1, d + n, SIZE_MAX);
    q.emplace(0, 0, 0);

    while (!q.empty())
    {
        auto const [u, dis, c] = q.top();
        q.pop();

        if ((!c && dis != d[u]) || (c && dis != f[u][c]))
            continue;

        for (auto const &e : g[u])
            if (c) // Color just changed.
            {
                if (dis + ccost[u][e.c] - e.p < d[e.v])
                {
                    d[e.v] = dis + ccost[u][e.c] - e.p;
                    q.emplace(e.v, d[e.v], 0);
                }
            }
            else
            {
                if (f[e.v].find(e.c) == f[e.v].end() || dis < f[e.v][e.c])
                {
                    f[e.v][e.c] = dis;
                    q.emplace(e.v, dis, 0);
                }
                if (dis + e.p < d[e.v])
                {
                    d[e.v] = dis + e.p;
                    q.emplace(e.v, d[e.v], 0);
                }
                if (dis + ccost[u][e.c] - e.p < d[e.v])
                {
                    d[e.v] = dis + ccost[u][e.c] - e.p;
                    q.emplace(e.v, d[e.v], e.c);
                }
            }
    }

    cout << (d[n - 1] == SIZE_MAX ? -1 : (int64_t)d[n - 1]) << '\n';
}

• Subtask 1: 0 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42