Submission #1293163

#	Time	Username	Problem	Language	Result	Execution time	Memory
1293163		Tymond	Olympic Bus (JOI20_ho_t4)	C++20	100 / 100	89 ms	2116 KiB

ho_t4

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define fi first
#define se second
#define vi vector<int>
#define vll vector<long long>
#define pii pair<int, int>
#define pll pair<long long, long long>
#define pb push_back
#define mp make_pair
#define eb emplace_back
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
mt19937_64 rng64(chrono::high_resolution_clock::now().time_since_epoch().count());
inline int rand(int l,int r){return uniform_int_distribution<int>(l, r)(rng);}
inline ll rand(ll l,ll r){return uniform_int_distribution<ll>(l, r)(rng64);}
#ifdef DEBUG
auto&operator<<(auto&o,pair<auto,auto>p){return o<<"("<<p.first<<", "<<p.second<<")";}
auto operator<<(auto&o,auto x)->decltype(x.end(),o){o<<"{";int i=0;for(auto e:x)o<<","+!i++<<e;return o<<"}";}
#define debug(X...)cerr<<"["#X"]: ",[](auto...$){((cerr<<$<<"; "),...)<<endl;}(X)
#else
#define debug(...){}
#endif

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

struct pair_hash{
  size_t operator()(const pair<int,int>&x)const{
    return hash<long long>()(((long long)x.first)^(((long long)x.second)<<32));
  }
}; 

struct Edge{
    int v, u, c, d;
    Edge(){
        v = u = c = d = 0;
    }

    Edge(int v1, int u1, int c1, int d1){
        v = v1;
        u = u1;
        c = c1;
        d = d1;
    }
};

const int MAXN = 207;
const int MAXM = 5e4 + 7;
const ll INF = 2e9;
vi g[2][MAXN];
ll dist[2][2][MAXN];
int back[2][2][MAXN];
Edge edges[MAXM];
int used[MAXN];
int n, m;
int special[MAXM];

void Dijkstra(int cur, int st){
    int start = (n - 1) * st + 1;
    for(int i = 1; i <= n; i++){
        dist[cur][st][i] = INF;
        back[cur][st][i] = 0;
        used[i] = 0;
    }
    dist[cur][st][start] = 0LL;
    dist[cur][st][0] = INF;
    int gId = (cur & 1);
    if(gId){
        for(int i = 1; i <= m; i++){
            swap(edges[i].u, edges[i].v);
        }
    }

    for(int k = 1; k <= n; k++){
        int best = 0;
        for(int i = 1; i <= n; i++){
            if(!used[i] && dist[cur][st][i] < dist[cur][st][best]){
                best = i;
            }
        }

        if(dist[cur][st][best] >= INF){
            break;
        }
        used[best] = 1;
        for(auto& e : g[gId][best]){
            if(dist[cur][st][edges[e].u] > dist[cur][st][best] + edges[e].c){
                dist[cur][st][edges[e].u] = dist[cur][st][best] + edges[e].c;
                back[cur][st][edges[e].u] = e;
            }
        }
    }

    int curr = n + 1 - start;
    while(curr){
        //cerr << curr << ' ' << back[cur][st][curr] << '\n';
       // cerr << edges[back[cur][st][curr]].v << '\n';
        special[back[cur][st][curr]] = 1;
        curr = edges[back[cur][st][curr]].v;
    }
   // debug(f);
    if(gId){
        for(int i = 1; i <= m; i++){
            swap(edges[i].u, edges[i].v);
        }
    }
}

int Dijkstra2(int start, int finish){
    vi dist2(n + 1, INF);
    dist2[start] = 0;
    for(int i = 1; i <= n; i++){
        used[i] = 0;
    }

    int best;
    for(int k = 1; k <= n; k++){
        best = 0;
        for(int i = 1; i <= n; i++){
            if(!used[i] && dist2[i] < dist2[best]){
                best = i;
            }
        }

        if(dist2[best] >= INF){
            break;
        }
        used[best] = 1;
        for(auto& e : g[0][best]){
            dist2[edges[e].u] = min(dist2[edges[e].u], dist2[best] + edges[e].c);
        }
    }
    return dist2[finish];
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
        
    cin >> n >> m;
    for(int i = 1; i <= m; i++){
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        g[0][a].pb(i);
        g[1][b].pb(i);
        edges[i] = Edge(a, b, c, d);
    }

    Dijkstra(0, 0);
    Dijkstra(0, 1);
    Dijkstra(1, 0);
    Dijkstra(1, 1);

    ll ans = (ll)dist[0][0][n] + dist[0][1][1];
    for(int i = 1; i <= m; i++){
        //cerr << "------\n";
        if(special[i]){
         //  cerr << "SPECIAL: " << i << '\n';
            g[0][edges[i].v].erase(find(all(g[0][edges[i].v]), i));
            g[0][edges[i].u].pb(i);
            swap(edges[i].v, edges[i].u);
            //cerr << Dijkstra2(1, n) << '\n';
           // cerr <<  Dijkstra2(n, 1) << '\n';
            ll now = (ll)Dijkstra2(1, n) + Dijkstra2(n, 1) + edges[i].d;
            g[0][edges[i].v].erase(find(all(g[0][edges[i].v]), i));
            g[0][edges[i].u].pb(i);
            swap(edges[i].v, edges[i].u);

            ans = min(ans, now);
        }else{
            //cerr << dist[0][0][n] << '\n';
            //cerr << dist[0][0][edges[i].u] << '\n';
            //cerr << dist[1][1][edges[i].v] << '\n';
            ll now = min(dist[0][0][n], (ll)dist[0][0][edges[i].u] + edges[i].c + dist[1][1][edges[i].v]) + edges[i].d;
            now += min(dist[0][1][1], (ll)dist[0][1][edges[i].u] + edges[i].c + dist[1][0][edges[i].v]);
           // cerr << min(dist[0][1][1], dist[0][1][edges[i].u] + edges[i].c + dist[1][0][edges[i].v]) << '\n';
           // cerr << now << '\n';
            ans = min(ans, now);
        }
    }

    if(ans >= INF){
        cout << "-1\n";
    }else{
        cout << ans << '\n';
    }

    return 0;
}

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