Submission #1081416

#	Time	Username	Problem	Language	Result	Execution time	Memory
1081416		Icelast	Robot (JOI21_ho_t4)	C++17	100 / 100	748 ms	158956 KiB

Main

#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 4e18+9;
vector<ll> dijkstra(int s, vector<vector<pair<ll, ll>>> &adj){
    int n = adj.size();
    vector<ll> dist(n+1, INF);
    dist[s] = 0;
    vector<bool> vis(n+1, false);
    priority_queue<pair<ll, ll>, vector<pair<ll, ll>>, greater<pair<ll, ll>>> pq;
    pq.push({0, s});
    while(!pq.empty()){
        ll d_u = pq.top().first;
        int u = pq.top().second;
        pq.pop();
        if(vis[u]){
            continue;
        }
        vis[u] = true;
        for(auto it : adj[u]){
            int v = it.first;
            ll w = it.second;
            if(vis[v]) continue;
            if(dist[v] > d_u+w){
                dist[v] = d_u+w;
                pq.push({dist[v], v});
            }
        }
    }
    return dist;
}
bool spfa(int s, vector<ll>& d, vector<vector<pair<ll, ll>>> adj) {
    int n = adj.size();
    d.assign(n+1, INF);
    vector<int> cnt(n+1, 0);
    vector<bool> inqueue(n+1, false);
    queue<int> q;

    d[s] = 0;
    q.push(s);
    inqueue[s] = true;
    while (!q.empty()) {
        int v = q.front();
        q.pop();
        inqueue[v] = false;

        for (auto edge : adj[v]) {
            int to = edge.first;
            ll len = edge.second;

            if (d[v] + len < d[to]) {
                d[to] = d[v] + len;
                if (!inqueue[to]) {
                    q.push(to);
                    inqueue[to] = true;
                    cnt[to]++;
                    if (cnt[to] > n)
                        return false;  // negative cycle
                }
            }
        }
    }
    return true;
}
struct road{
    ll v, c, p;
};
void solve(){
    int n, m;
    cin >> n >> m;
    vector<vector<road>> adj(n+1);
    for(int i = 1; i <= m; i++){
        int u, v, c, p;
        cin >> u >> v >> c >> p;
        adj[u].push_back({v, c, p});
        adj[v].push_back({u, c, p});
    }
    vector<bool> vis(n+1, false);
    auto dfs = [&](auto dfs, int u) -> void{
        vis[u] = true;
        for(auto it : adj[u]){
            int v = it.v;
            if(vis[v]) continue;
            dfs(dfs, v);
        }
    };
    dfs(dfs, 1);
    if(!vis[n]){
        cout << -1;
        return;
    }
    vector<map<int, int>> mp(n+1), nn(n+1);
    vector<map<int, vector<int>>> to(n+1);
    vector<map<ll, ll>> sum(n+1);
    int N = n;
    for(int i = 1; i <= n; i++){
        for(auto it : adj[i]){
            mp[i][it.c]++;
            to[i][it.c].push_back(it.v);
            sum[i][it.c]+=it.p;
            if(nn[i][it.c] == 0){
                N++;
                nn[i][it.c] = N;
            }
        }
    }
    vector<vector<pair<ll, ll>>> adj2(N+1);
    for(int i = 1; i <= n; i++){
        for(auto it : adj[i]){
            adj2[i].push_back({it.v, it.p});
            adj2[i].push_back({nn[i][it.c], 0});
            adj2[nn[i][it.c]].push_back({it.v, sum[i][it.c]-it.p});
            adj2[i].push_back({nn[it.v][it.c], 0});
        }
    }
    vector<ll> dist(N+1, INF);
    dist = dijkstra(1, adj2);
    cout << dist[n];
}
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    solve();
}

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