Submission #486046

#	Time	Username	Problem	Language	Result	Execution time	Memory
486046		Jarif_Rahman	Olympic Bus (JOI20_ho_t4)	C++17	0 / 100	61 ms	9248 KiB

ho_t4

#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
const ll inf = 1e17;

vector<ll> dijkstra(vector<vector<pair<ll, int>>> v, int source){
    int n = v.size();

    vector<ll> dis(n, inf);
    vector<bool> bl(n, 0);
    priority_queue<pair<ll, int>> pq;

    dis[source] = 0;
    pq.push({0, source});

    while(!pq.empty()){
        int nd = pq.top().sc; pq.pop();
        if(bl[nd]) continue;
        bl[nd] = 1;
        for(auto [w, x]: v[nd]) if(dis[nd]+w < dis[x]){
            dis[x] = dis[nd]+w;
            pq.push({-dis[x], x});
        }
    }

    return dis;
}

vector<ll> d1, d2, d3, d4;
vector<vector<pair<ll, int>>> v, vr;
map<array<int, 3>, int> mp;
vector<bool> s1, s2;
vector<bool> bl1, bl2;
vector<int> ddd1, ddd2;

void dfs_1(int nd, int d){
    if(bl1[nd]){
        return;
    }
    bl1[nd] = 1;
    ddd1[nd] = d;
    for(auto [w, x]: v[nd]) dfs_1(x, d+1);
}

void dfs_2(int nd, int d){
    if(bl2[nd]){
        return;
    }
    bl2[nd] = 1;
    ddd2[nd] = d;
    for(auto [w, x]: v[nd]) dfs_2(x, d+1);
}

void dfs1(int nd){
    for(auto [w, x]: vr[nd]) if(d1[x] < d1[nd] || (d1[x] == d1[nd] && ddd1[x] < ddd1[nd])){
        s1[mp[{x, nd, (int)w}]] = 1;
        dfs1(x);
        break;
    }
}

void dfs2(int nd){
    for(auto [w, x]: vr[nd]) if(d3[x] < d3[nd] || (d3[x] == d3[nd] && ddd2[x] < ddd2[nd])){
        s2[mp[{x, nd, (int)w}]] = 1;
        dfs2(x);
        break;
    }
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m; cin >> n >> m;

    vector<array<int, 4>> e(m);
    v.resize(n);
    vr.resize(n);

    for(int i = 0; i < m; i++){
        cin >> e[i][0] >> e[i][1] >> e[i][2] >> e[i][3];
        e[i][0]--, e[i][1]--;

        mp[{e[i][0], e[i][1], e[i][2]}] = i;

        v[e[i][0]].pb({e[i][2], e[i][1]});
        vr[e[i][1]].pb({e[i][2], e[i][0]});
    }

    s1.assign(m, 0), s2.assign(m, 0);

    d1 = dijkstra(v, 0), d2 = dijkstra(vr, n-1), d3 = dijkstra(v, n-1), d4 = dijkstra(vr, 0);

    bl1.assign(n, 0);
    bl2.assign(n, 0);
    ddd1.assign(n, 0);
    ddd2.assign(n, 0);

    dfs_1(0, 0);
    dfs_2(n-1, 0);

    dfs1(n-1);
    dfs2(0);

    ll ans = inf;

    ans = min(ans, d1[n-1]+d3[0]);

    for(int i = 0; i < m; i++){
        int a = e[i][0], b = e[i][1];
        ll w = e[i][2], c = e[i][3];
        if(!s2[i]){
            ans = min(ans, c+d1[b]+w+d2[a]+d3[0]);
            continue;
        }

        vector<vector<pair<ll, int>>> v0(n);

        for(int j = 0; j < m; j++){
            if(j == i) v0[e[j][1]].pb({e[j][2], e[j][0]});
            else v0[e[j][0]].pb({e[j][2], e[j][1]});
        }

        auto dd1 = dijkstra(v0, 0), dd2 = dijkstra(v0, n-1);
        ans = min(ans, dd1[n-1]+dd2[0]);
    }

    for(int i = 0; i < m; i++){
        int a = e[i][0], b = e[i][1];
        ll w = e[i][2], c = e[i][3];
        if(!s1[i]){
            ans = min(ans, c+d1[n-1]+d3[b]+w+d4[a]);
            continue;
        }

        vector<vector<pair<ll, int>>> v0(n);

        for(int j = 0; j < m; j++){
            if(j == i) v0[e[j][1]].pb({e[j][2], e[j][0]});
            else v0[e[j][0]].pb({e[j][2], e[j][1]});
        }

        auto dd1 = dijkstra(v0, 0), dd2 = dijkstra(v0, n-1);
        ans = min(ans, dd1[n-1]+dd2[0]);
    }

    if(ans >= inf) ans = -1;
    cout << ans << "\n";

}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 21
• Subtask 4: 0 / 63