Submission #486336

#TimeUsernameProblemLanguageResultExecution timeMemory
486336Jarif_RahmanOlympic Bus (JOI20_ho_t4)C++17
100 / 100
730 ms6520 KiB
#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<array<int, 3>>> 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, c, x]: v[nd]) if(dis[nd]+w < dis[x]){
            dis[x] = dis[nd]+w;
            pq.push({-dis[x], x});
        }
    }
 
    return dis;
}
 
int e[50000][4];
 
vector<ll> d1, d2, d3, d4;
vector<vector<array<int, 3>>> v, vr;
vector<bool> s1, s2;
vector<bool> bl1, bl2;
int ddd1[200], ddd2[200];
 
void dfs_1(int nd, int d){
    if(bl1[nd]){
        return;
    }
    bl1[nd] = 1;
    ddd1[nd] = d;
    for(auto [w, c, 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, c, x]: v[nd]) dfs_2(x, d+1);
}
 
void dfs1(int nd){
    for(auto [w, c, x]: vr[nd]) if((d1[x] < d1[nd] || (d1[x] == d1[nd] && ddd1[x] < ddd1[nd])) && d1[x]+w == d1[nd]){
        s1[c] = 1;
        dfs1(x);
        break;
    }
}
 
void dfs2(int nd){
    for(auto [w, c, x]: vr[nd]) if((d3[x] < d3[nd] || (d3[x] == d3[nd] && ddd2[x] < ddd2[nd])) && d3[x]+w == d3[nd]){
        s2[c] = 1;
        dfs2(x);
        break;
    }
}
 
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m; cin >> n >> 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]--;
 
        v[e[i][0]].pb({e[i][2], i, e[i][1]});
        vr[e[i][1]].pb({e[i][2], i, 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);
    
    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] && !s1[i]){
            ans = min(ans, c+d1[b]+w+d2[a]+d3[0]);
            ans = min(ans, c+d1[n-1]+d3[b]+w+d4[a]);
            ans = min(ans, c+d1[b]+w+d2[a]+d3[b]+w+d4[a]);
            continue;
        }
 
        vector<vector<array<int, 3>>> v0(n);
 
        for(int j = 0; j < m; j++){
            if(j == i) v0[e[j][1]].pb({e[j][2], e[j][3], e[j][0]});
            else v0[e[j][0]].pb({e[j][2], e[j][3], e[j][1]});
        }

        if(!s2[i]){
            auto dd1 = dijkstra(v0, 0);
            ans = min(ans, dd1[n-1]+d3[0]+e[i][3]);
            ans = min(ans, dd1[n-1]+d3[b]+w+d4[a]+e[i][3]);
        }
        else if(!s1[i]){
            auto dd2 = dijkstra(v0, n-1);
            ans = min(ans, d1[n-1]+dd2[0]+e[i][3]);
            ans = min(ans, d1[b]+w+d2[a]+dd2[0]+e[i][3]);
        }
        else{
            auto dd1 = dijkstra(v0, 0), dd2 = dijkstra(v0, n-1);
            ans = min(ans, dd1[n-1]+dd2[0]+e[i][3]);
        }
    }
 
    if(ans >= inf) ans = -1;
    cout << ans << "\n";
 
}
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