Submission #1081507

#	Time	Username	Problem	Language	Result	Execution time	Memory
1081507		Pannda	Robot (JOI21_ho_t4)	C++17	100 / 100	427 ms	104868 KiB

Main

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

template <class T>
vector<T> dijkstra(const vector<vector<pair<int, T>>> &adj, vector<T> dist) {
    int n = adj.size();
    priority_queue<pair<T, int>, vector<pair<T, int>>, greater<>> pq;
    for (int u = 0; u < n; u++) {
        pq.push({dist[u], u});
    }
    while (!pq.empty()) {
        auto [d, u] = pq.top();
        pq.pop();
        if (d != dist[u]) continue;
        for (auto [v, w] : adj[u]) {
            if (dist[u] + w < dist[v]) {
                dist[v] = dist[u] + w;
                pq.push({dist[v], v});
            }
        }
    }
    return dist;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    struct Edge {
        int v, color, cost;
    };
    vector<vector<Edge>> edges(n);
    vector<vector<int>> colors(n);
    for (int i = 0; i < m; i++) {
        int u, v, color, cost;
        cin >> u >> v >> color >> cost;
        u--; v--;
        edges[u].push_back({v, color, cost});
        edges[v].push_back({u, color, cost});
        colors[u].push_back(color);
        colors[v].push_back(color);
    }

    for (int u = 0; u < n; u++) {
        sort(colors[u].begin(), colors[u].end());
        colors[u].resize(unique(colors[u].begin(), colors[u].end()) - colors[u].begin());
    }
    auto f = [&](int u, int color) -> int {
        int i = lower_bound(colors[u].begin(), colors[u].end(), color) - colors[u].begin();
        assert(i < colors[u].size());
        return i;
    };

    vector<vector<long long>> sum(n);
    vector<vector<int>> id(n);
    int tim = n;
    for (int u = 0; u < n; u++) {
        sum[u].resize(colors[u].size(), 0);
        for (auto [v, color, cost] : edges[u]) {
            sum[u][f(u, color)] += cost;
        }
        id[u].resize(colors[u].size());
        iota(id[u].begin(), id[u].end(), tim);
        tim += colors[u].size();
    }

    vector<vector<pair<int, long long>>> adj(tim);
    for (int u = 0; u < n; u++) {
        for (auto [v, color, cost] : edges[u]) {
//            (u) -> (v) + cost;
//            (u) -> (v) + sum[f(u, color)][i] - cost
//            (u) -> (v, color) + 0
//            (u, color) -> (v) + sum[u][f(u, color)] - cost
            int i = f(u, color);
            int j = f(v, color);
            adj[u].push_back({v, cost});
            adj[u].push_back({v, sum[u][i] - cost});
            adj[u].push_back({ id[v][j], 0 });
            adj[id[u][i]].push_back({v, sum[u][i] - cost});
        }
    }

    const long long INF = 4e18;
    vector<long long> dist(tim, INF);
    dist[0] = 0;
    dist = dijkstra(adj, dist);

    if (dist[n - 1] == INF) {
        cout << -1 << '\n';
    } else {
        cout << dist[n - 1] << '\n';
    }
}

Compilation message (stderr)

In file included from /usr/include/c++/10/cassert:44,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
                 from Main.cpp:1:
Main.cpp: In lambda function:
Main.cpp:53:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |         assert(i < colors[u].size());
      |                ~~^~~~~~~~~~~~~~~~~~

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