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Submission #758231

# Submission time Handle Problem Language Result Execution time Memory
758231 2023-06-14T09:48:35 Z jasmin Olympic Bus (JOI20_ho_t4) C++17
100 / 100
 993 ms 4208 KB 
#include<bits/stdc++.h>
using namespace std;
#define ll long long

const ll INF=1e17;
vector<int> c;
vector<int> d;

struct graph{
    vector<vector<pair<int,int> > >adi;

    graph(int n, int m){
        adi.assign(n, {});
    }

};

void dijkstra(int start, vector<ll>& dist, vector<int>& par, int n, graph& g){

    dist.assign(n, INF);
    par.assign(n, -1);
    vector<bool> vis(n, false);
    priority_queue<pair<int,int> > pq;

    dist[start]=0;
    pq.push({-0, start});

    while(!pq.empty()){
        int v=pq.top().second;
        pq.pop();

        if(vis[v]){
            continue;
        }
        vis[v]=true;

        for(auto [u, ind]: g.adi[v]){

            if(dist[v]+c[ind] < dist[u]){
                par[u]=ind;
                dist[u] = dist[v] + c[ind];
                pq.push({-dist[u], u});
            }

        }
    }

}

vector<int> find_sp(int a, int b, vector<int>& par, vector<pair<int,int> >& edge, int m){
    vector<int> p;
    if(par[b]==-1){
        return {};
    }
    
    int v=b;
    while(v!=a){

        p.push_back(par[v]);
        v=edge[par[v]].first;
    }

    reverse(p.begin(), p.end());
    return p;
}

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

    int n, m;
    cin >> n >> m;
    c.assign(m, 0);
    d.assign(m, 0);
    graph g(n, m);
    graph rev(n, m);
    vector<pair<int,int> > edge(m);
    for(int i=0; i<m; i++){
        int a, b;
        cin >> a >> b >> c[i] >> d[i];

        a--; b--;
        g.adi[a].push_back({b, i});
        rev.adi[b].push_back({a, i});

        edge[i]={a, b};
    }

    //distances
    vector<int> par0(n, -1);
    vector<ll> to0(n, INF);
    dijkstra(0, to0, par0, n, rev);
    vector<ll> from0(n, INF);
    dijkstra(0, from0, par0, n, g);

    vector<int> parn(n, -1);
    vector<ll> ton(n, INF);
    dijkstra(n-1, ton, parn, n, rev);
    vector<ll> fromn(n, INF);
    dijkstra(n-1, fromn, parn, n, g);


    //paths
    vector<int> path1=find_sp(0, n-1, par0, edge, m);
    vector<int> path2=find_sp(n-1, 0, parn, edge, m);
    
    vector<bool> used(m, false);
    for(auto e: path1){
        used[e]=true;
    }
    for(auto e: path2){
        used[e]=true;
    }


    //possibility 0: turning no edge
    ll ans=INF;
    ans = min(ans, from0[n-1] + fromn[0]);

    //possibility 1: edge not on path
    for(int i=0; i<m; i++){
        if(used[i]) continue;

        auto [a, b]=edge[i];

        ll d1=min(from0[b] + c[i] + ton[a], from0[n-1]);
        ll d2=min(fromn[b] + c[i] + to0[a], fromn[0]);

        ll dis=d1 + d2 + d[i];

        ans=min(ans, dis);
    }

    //possibility 2: edge on path
    for(int e=0; e<m; e++){
        if(!used[e]) continue;

        graph neu(n, m);
        for(int i=0; i<m; i++){

            auto [a, b]=edge[i];
            if(i==e){
                neu.adi[b].push_back({a, i});
            }
            else{
                neu.adi[a].push_back({b, i});
            }
        }

        ll dis=d[e];
        vector<ll> dist(n, INF);
        vector<int> p(n, -1);
        dijkstra(0, dist, p, n, neu);
        dis += dist[n-1];

        dijkstra(n-1, dist, p, n, neu);
        dis+=dist[0];

        ans=min(ans, dis);
    }

    //output
    if(ans==INF){
        cout << -1 << "\n";
    }
    else{
        cout << ans << "\n";
    }
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 2 ms 340 KB Output is correct
4 Correct 2 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 26 ms 340 KB Output is correct
11 Correct 33 ms 340 KB Output is correct
12 Correct 31 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 2 ms 340 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 3016 KB Output is correct
2 Correct 30 ms 3000 KB Output is correct
3 Correct 27 ms 3040 KB Output is correct
4 Correct 2 ms 340 KB Output is correct
5 Correct 2 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 340 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 19 ms 2380 KB Output is correct
10 Correct 18 ms 2388 KB Output is correct
11 Correct 30 ms 3028 KB Output is correct
12 Correct 29 ms 2948 KB Output is correct
13 Correct 29 ms 2996 KB Output is correct
14 Correct 31 ms 3224 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 17 ms 2320 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 27 ms 2916 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 17 ms 2388 KB Output is correct
9 Correct 17 ms 2420 KB Output is correct
10 Correct 22 ms 2968 KB Output is correct
11 Correct 20 ms 2896 KB Output is correct
12 Correct 21 ms 3056 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 0 ms 212 KB Output is correct
19 Correct 21 ms 3108 KB Output is correct
20 Correct 21 ms 2948 KB Output is correct
21 Correct 19 ms 2924 KB Output is correct
22 Correct 21 ms 2956 KB Output is correct

Subtask #4
63.0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 2 ms 340 KB Output is correct
4 Correct 2 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 26 ms 340 KB Output is correct
11 Correct 33 ms 340 KB Output is correct
12 Correct 31 ms 340 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 2 ms 340 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 2 ms 340 KB Output is correct
17 Correct 26 ms 3016 KB Output is correct
18 Correct 30 ms 3000 KB Output is correct
19 Correct 27 ms 3040 KB Output is correct
20 Correct 2 ms 340 KB Output is correct
21 Correct 2 ms 340 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 0 ms 340 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 19 ms 2380 KB Output is correct
26 Correct 18 ms 2388 KB Output is correct
27 Correct 30 ms 3028 KB Output is correct
28 Correct 29 ms 2948 KB Output is correct
29 Correct 29 ms 2996 KB Output is correct
30 Correct 31 ms 3224 KB Output is correct
31 Correct 2 ms 340 KB Output is correct
32 Correct 1 ms 340 KB Output is correct
33 Correct 17 ms 2320 KB Output is correct
34 Correct 0 ms 340 KB Output is correct
35 Correct 27 ms 2916 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 17 ms 2388 KB Output is correct
39 Correct 17 ms 2420 KB Output is correct
40 Correct 22 ms 2968 KB Output is correct
41 Correct 20 ms 2896 KB Output is correct
42 Correct 21 ms 3056 KB Output is correct
43 Correct 1 ms 212 KB Output is correct
44 Correct 0 ms 212 KB Output is correct
45 Correct 1 ms 212 KB Output is correct
46 Correct 1 ms 212 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 0 ms 212 KB Output is correct
49 Correct 21 ms 3108 KB Output is correct
50 Correct 21 ms 2948 KB Output is correct
51 Correct 19 ms 2924 KB Output is correct
52 Correct 21 ms 2956 KB Output is correct
53 Correct 31 ms 2896 KB Output is correct
54 Correct 34 ms 2892 KB Output is correct
55 Correct 30 ms 2984 KB Output is correct
56 Correct 2 ms 340 KB Output is correct
57 Correct 2 ms 340 KB Output is correct
58 Correct 213 ms 2340 KB Output is correct
59 Correct 264 ms 2356 KB Output is correct
60 Correct 340 ms 2384 KB Output is correct
61 Correct 243 ms 2340 KB Output is correct
62 Correct 230 ms 2348 KB Output is correct
63 Correct 313 ms 2340 KB Output is correct
64 Correct 678 ms 2836 KB Output is correct
65 Correct 800 ms 2860 KB Output is correct
66 Correct 993 ms 2864 KB Output is correct
67 Correct 16 ms 3076 KB Output is correct
68 Correct 20 ms 3548 KB Output is correct
69 Correct 25 ms 3504 KB Output is correct
70 Correct 34 ms 4060 KB Output is correct
71 Correct 30 ms 4080 KB Output is correct
72 Correct 25 ms 4032 KB Output is correct
73 Correct 28 ms 4208 KB Output is correct
74 Correct 30 ms 4160 KB Output is correct