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Submission #815691

# Submission time Handle Problem Language Result Execution time Memory
815691 2023-08-08T18:44:22 Z anton Olympic Bus (JOI20_ho_t4) C++17
11 / 100
 56 ms 4804 KB 
#include<bits/stdc++.h>

using namespace std;
#define int long long
#define pii pair<int, int>


struct Edge{
    int u, v, c, d;
    Edge(){};
};

const int MAX_E = 5*1e4;
const int MAX_V = 200;
const int INF = 1e15;
int v, e;
Edge edges[MAX_E];
vector<pii> adj[MAX_V];

int find_len(int begin, int dest){
    vector<int> dist(v, INF);
    vector<pii> prev(v, pii(-1, -1));
    dist[begin] = 0;

    priority_queue<pii> pq;
    pq.push(pii(0, begin));

    while(pq.size()>0){
        auto cur = pq.top();
        pq.pop();

        int u = cur.second;
        int u_dist = -cur.first;

        if(dist[u] == u_dist){
            //cout<<u<<" "<<dist[u]<<endl;
            for(auto next: adj[u]){
                int next_dist = u_dist + edges[next.second].c;
                if(next_dist< dist[next.first]){
                    dist[next.first] = next_dist;
                    pq.push(pii(-next_dist, next.first));
                    prev[next.first].first = u;
                    prev[next.first].second = next.second;
                }
            }
        }
    }
    return dist[dest];
}
vector<int> find_path(int begin, int dest){
    vector<int> dist(v, INF);
    vector<pii> prev(v, pii(-1, -1));
    dist[begin] = 0;

    priority_queue<pii> pq;
    pq.push(pii(0, begin));

    while(pq.size()>0){
        auto cur = pq.top();
        pq.pop();

        int u = cur.second;
        int u_dist = -cur.first;

        if(dist[u] == u_dist){
            //cout<<u<<" "<<dist[u]<<endl;
            for(auto next: adj[u]){
                int next_dist = u_dist + edges[next.second].c;
                if(next_dist< dist[next.first]){
                    dist[next.first] = next_dist;
                    pq.push(pii(-next_dist, next.first));
                    prev[next.first].first = u;
                    prev[next.first].second = next.second;
                }
            }
        }
    }

    if(dist[dest] == INF){
        return vector<int>(0);
    }
    else{
        int cur = dest;
        vector<int> res;
        while(cur!=begin){
            res.push_back(prev[cur].second);
            cur = prev[cur].first;
        }
        return res;
    }
}

int d[MAX_V][MAX_V];
bool is_path[MAX_E];

void find_d(){
    for(int i = 0; i<v; i++){
        for(int j = 0; j<v; j++){
            d[i][j] = INF;
        }
        adj[i].clear();
    }

    for(int i = 0; i<v; i++){
        d[i][i] = 0;
    }
    for(int i = 0; i<e; i++){
            
        d[edges[i].u][edges[i].v] = min(d[edges[i].u][edges[i].v], edges[i].c);
        adj[edges[i].u].push_back(pii(edges[i].v, i));
    }
}

void floyd(){
    for(int mid= 0; mid<v; mid++){
        for(int f= 0; f<v; f++){
            for(int l = 0; l<v; l++){
                d[f][l] = min(d[f][l], d[f][mid] + d[mid][l]);
            }
        }
    }
}

signed main(){
    cin>>v>>e;


    for(int i = 0; i<e; i++){
        cin>>edges[i].u>>edges[i].v>>edges[i].c>>edges[i].d;
        edges[i].u--;
        edges[i].v--;

        //adj[edges[i].u].push_back(pii(edges[i].v, i));
        //d[edges[i].u][edges[i].v] = min(d[edges[i].u][edges[i].v], edges[i].c);
    }

    find_d();

    auto p1 = find_path(0, v-1);
    auto p2 = find_path(v-1, 0);

    if(p1.size()>201||p2.size()>201){
        return 4;
    }
    for(auto e : p1){
        is_path[e] = true;
    }
    for(auto e: p2){
        is_path[e] = true;
    }
    floyd();

    int res = d[0][v-1] + d[v-1][0];

    //cout<<go<<" "<<back<<endl;

    for(int i = 0; i<e; i++){
        //if(!is_path[i]){
            int from = edges[i].v;
            int to = edges[i].u;
            res = min(res, min(d[0][v-1], d[0][from] + edges[i].c + d[to][v-1] ) + min(d[v-1][0], d[v-1][from] + edges[i].c + d[to][0])+  edges[i].d);
        //}
    }

    for(int i = 0; i<e; i++){
        if(is_path[i]){
            swap(edges[i].u, edges[i].v);
            find_d();
            swap(edges[i].u, edges[i].v);
            res = min(res, find_len(0, v-1) + find_len(v-1, 0) +edges[i].d);
        }
    }

    if(res>=INF){
        cout<<-1<<endl;
        return 0;
    }

    cout<<res<<endl;
}

Subtask #1
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 576 KB Output is correct
2 Correct 7 ms 596 KB Output is correct
3 Correct 9 ms 596 KB Output is correct
4 Correct 9 ms 596 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 7 ms 636 KB Output is correct
7 Incorrect 0 ms 212 KB Output isn't correct
8 Halted 0 ms 0 KB -

Subtask #2
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 50 ms 3544 KB Output is correct
2 Correct 53 ms 3536 KB Output is correct
3 Correct 54 ms 3556 KB Output is correct
4 Correct 9 ms 724 KB Output is correct
5 Correct 9 ms 588 KB Output is correct
6 Correct 7 ms 668 KB Output is correct
7 Correct 7 ms 596 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 47 ms 3404 KB Output is correct
10 Correct 48 ms 4628 KB Output is correct
11 Correct 56 ms 4612 KB Output is correct
12 Correct 55 ms 4804 KB Output is correct
13 Correct 53 ms 4672 KB Output is correct
14 Correct 54 ms 4784 KB Output is correct

Subtask #3
0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 596 KB Output is correct
2 Correct 8 ms 644 KB Output is correct
3 Correct 39 ms 2704 KB Output is correct
4 Correct 7 ms 596 KB Output is correct
5 Correct 46 ms 3372 KB Output is correct
6 Incorrect 0 ms 212 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #4
0 / 63.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 576 KB Output is correct
2 Correct 7 ms 596 KB Output is correct
3 Correct 9 ms 596 KB Output is correct
4 Correct 9 ms 596 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 7 ms 636 KB Output is correct
7 Incorrect 0 ms 212 KB Output isn't correct
8 Halted 0 ms 0 KB -