oj.uz

Submission #758228

# Submission time Handle Problem Language Result Execution time Memory
758228 2023-06-14T09:45:27 Z jasmin Olympic Bus (JOI20_ho_t4) C++17
37 / 100
 1000 ms 6096 KB 
#include<bits/stdc++.h>
using namespace std;
#define int long long

const int 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<int>& 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<int> to0(n, INF);
    dijkstra(0, to0, par0, n, rev);
    vector<int> from0(n, INF);
    dijkstra(0, from0, par0, n, g);

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

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

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

        ans=min(ans, dis);
    }

    //possibility 2: edge on path
    vector<int> path;
    for(int i=0; i<m; i++){
        if(used[i]) path.push_back(i);
    }

    for(auto e: path){

        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});
            }
        }

        int dis=d[e];
        vector<int> 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 468 KB Output is correct
4 Correct 3 ms 472 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 28 ms 468 KB Output is correct
11 Correct 41 ms 468 KB Output is correct
12 Correct 41 ms 468 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 31 ms 5580 KB Output is correct
2 Correct 32 ms 5644 KB Output is correct
3 Correct 29 ms 5696 KB Output is correct
4 Correct 2 ms 468 KB Output is correct
5 Correct 2 ms 468 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 272 KB Output is correct
9 Correct 20 ms 4480 KB Output is correct
10 Correct 24 ms 4380 KB Output is correct
11 Correct 33 ms 5628 KB Output is correct
12 Correct 38 ms 5636 KB Output is correct
13 Correct 43 ms 5644 KB Output is correct
14 Correct 33 ms 6096 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 30 ms 4236 KB Output is correct
4 Correct 0 ms 340 KB Output is correct
5 Correct 23 ms 5480 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 31 ms 4460 KB Output is correct
9 Correct 18 ms 4436 KB Output is correct
10 Correct 34 ms 5488 KB Output is correct
11 Correct 27 ms 5540 KB Output is correct
12 Correct 38 ms 5732 KB Output is correct
13 Correct 0 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 0 ms 212 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 1 ms 212 KB Output is correct
19 Correct 27 ms 5840 KB Output is correct
20 Correct 21 ms 5528 KB Output is correct
21 Correct 21 ms 5520 KB Output is correct
22 Correct 26 ms 5432 KB Output is correct

Subtask #4
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 468 KB Output is correct
4 Correct 3 ms 472 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 28 ms 468 KB Output is correct
11 Correct 41 ms 468 KB Output is correct
12 Correct 41 ms 468 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 31 ms 5580 KB Output is correct
18 Correct 32 ms 5644 KB Output is correct
19 Correct 29 ms 5696 KB Output is correct
20 Correct 2 ms 468 KB Output is correct
21 Correct 2 ms 468 KB Output is correct
22 Correct 1 ms 340 KB Output is correct
23 Correct 1 ms 340 KB Output is correct
24 Correct 1 ms 272 KB Output is correct
25 Correct 20 ms 4480 KB Output is correct
26 Correct 24 ms 4380 KB Output is correct
27 Correct 33 ms 5628 KB Output is correct
28 Correct 38 ms 5636 KB Output is correct
29 Correct 43 ms 5644 KB Output is correct
30 Correct 33 ms 6096 KB Output is correct
31 Correct 2 ms 340 KB Output is correct
32 Correct 1 ms 340 KB Output is correct
33 Correct 30 ms 4236 KB Output is correct
34 Correct 0 ms 340 KB Output is correct
35 Correct 23 ms 5480 KB Output is correct
36 Correct 1 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 31 ms 4460 KB Output is correct
39 Correct 18 ms 4436 KB Output is correct
40 Correct 34 ms 5488 KB Output is correct
41 Correct 27 ms 5540 KB Output is correct
42 Correct 38 ms 5732 KB Output is correct
43 Correct 0 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 0 ms 212 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 1 ms 212 KB Output is correct
49 Correct 27 ms 5840 KB Output is correct
50 Correct 21 ms 5528 KB Output is correct
51 Correct 21 ms 5520 KB Output is correct
52 Correct 26 ms 5432 KB Output is correct
53 Correct 29 ms 5316 KB Output is correct
54 Correct 37 ms 5520 KB Output is correct
55 Correct 50 ms 5540 KB Output is correct
56 Correct 3 ms 340 KB Output is correct
57 Correct 2 ms 468 KB Output is correct
58 Correct 265 ms 4308 KB Output is correct
59 Correct 310 ms 4460 KB Output is correct
60 Correct 437 ms 4516 KB Output is correct
61 Correct 268 ms 4456 KB Output is correct
62 Correct 285 ms 4456 KB Output is correct
63 Correct 446 ms 4308 KB Output is correct
64 Correct 836 ms 5164 KB Output is correct
65 Correct 892 ms 5224 KB Output is correct
66 Execution timed out 1068 ms 5884 KB Time limit exceeded
67 Halted 0 ms 0 KB -