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Submission #758223

# Submission time Handle Problem Language Result Execution time Memory
758223 2023-06-14T09:41:13 Z jasmin Olympic Bus (JOI20_ho_t4) C++17
37 / 100
 1000 ms 8892 KB 
#include<bits/stdc++.h>
using namespace std;
#define int long long

const int INF=1e17;

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

    graph(int n, int m){
        adi.assign(n, {});
        c.assign(m, 0);
        d.assign(m, 0);
    }

};

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]+g.c[ind] < dist[u]){
                par[u]=ind;
                dist[u] = dist[v] + g.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;
    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 >> g.c[i] >> g.d[i];
        a--; b--;
        g.adi[a].push_back({b, i});

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

        int d=d1 + d2 + g.d[i];

        ans=min(ans, d);
    }

    //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++){
            neu.c[i]=g.c[i];
            neu.d[i]=g.d[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=g.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 468 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 3 ms 468 KB Output is correct
4 Correct 2 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 32 ms 508 KB Output is correct
11 Correct 53 ms 488 KB Output is correct
12 Correct 41 ms 468 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 3 ms 468 KB Output is correct
15 Correct 2 ms 456 KB Output is correct
16 Correct 2 ms 456 KB Output is correct

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 39 ms 7172 KB Output is correct
2 Correct 35 ms 7204 KB Output is correct
3 Correct 38 ms 7244 KB Output is correct
4 Correct 3 ms 596 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 0 ms 212 KB Output is correct
9 Correct 19 ms 5156 KB Output is correct
10 Correct 22 ms 6344 KB Output is correct
11 Correct 47 ms 8380 KB Output is correct
12 Correct 36 ms 8364 KB Output is correct
13 Correct 40 ms 8320 KB Output is correct
14 Correct 46 ms 8892 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 22 ms 5436 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 27 ms 7004 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 18 ms 5204 KB Output is correct
9 Correct 20 ms 6160 KB Output is correct
10 Correct 31 ms 7980 KB Output is correct
11 Correct 23 ms 8036 KB Output is correct
12 Correct 26 ms 8108 KB Output is correct
13 Correct 1 ms 212 KB Output is correct
14 Correct 0 ms 316 KB Output is correct
15 Correct 1 ms 340 KB Output is correct
16 Correct 1 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 32 ms 8432 KB Output is correct
20 Correct 25 ms 8040 KB Output is correct
21 Correct 23 ms 8008 KB Output is correct
22 Correct 27 ms 7892 KB Output is correct

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 468 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 3 ms 468 KB Output is correct
4 Correct 2 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 32 ms 508 KB Output is correct
11 Correct 53 ms 488 KB Output is correct
12 Correct 41 ms 468 KB Output is correct
13 Correct 1 ms 340 KB Output is correct
14 Correct 3 ms 468 KB Output is correct
15 Correct 2 ms 456 KB Output is correct
16 Correct 2 ms 456 KB Output is correct
17 Correct 39 ms 7172 KB Output is correct
18 Correct 35 ms 7204 KB Output is correct
19 Correct 38 ms 7244 KB Output is correct
20 Correct 3 ms 596 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 0 ms 212 KB Output is correct
25 Correct 19 ms 5156 KB Output is correct
26 Correct 22 ms 6344 KB Output is correct
27 Correct 47 ms 8380 KB Output is correct
28 Correct 36 ms 8364 KB Output is correct
29 Correct 40 ms 8320 KB Output is correct
30 Correct 46 ms 8892 KB Output is correct
31 Correct 2 ms 468 KB Output is correct
32 Correct 1 ms 340 KB Output is correct
33 Correct 22 ms 5436 KB Output is correct
34 Correct 1 ms 340 KB Output is correct
35 Correct 27 ms 7004 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 18 ms 5204 KB Output is correct
39 Correct 20 ms 6160 KB Output is correct
40 Correct 31 ms 7980 KB Output is correct
41 Correct 23 ms 8036 KB Output is correct
42 Correct 26 ms 8108 KB Output is correct
43 Correct 1 ms 212 KB Output is correct
44 Correct 0 ms 316 KB Output is correct
45 Correct 1 ms 340 KB Output is correct
46 Correct 1 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 32 ms 8432 KB Output is correct
50 Correct 25 ms 8040 KB Output is correct
51 Correct 23 ms 8008 KB Output is correct
52 Correct 27 ms 7892 KB Output is correct
53 Correct 34 ms 7984 KB Output is correct
54 Correct 50 ms 8256 KB Output is correct
55 Correct 41 ms 8076 KB Output is correct
56 Correct 3 ms 468 KB Output is correct
57 Correct 2 ms 468 KB Output is correct
58 Correct 328 ms 6512 KB Output is correct
59 Correct 386 ms 6556 KB Output is correct
60 Correct 502 ms 6524 KB Output is correct
61 Correct 338 ms 6444 KB Output is correct
62 Correct 332 ms 6452 KB Output is correct
63 Correct 611 ms 6576 KB Output is correct
64 Correct 899 ms 7344 KB Output is correct
65 Execution timed out 1073 ms 7336 KB Time limit exceeded
66 Halted 0 ms 0 KB -