Submission #583529

#	Time	Username	Problem	Language	Result	Execution time	Memory
583529		AngusWong	Robot (JOI21_ho_t4)	C++17	0 / 100	3068 ms	67616 KiB

Main

#include <bits/stdc++.h>
#define ll long long
#define pll pair<ll, ll>
#define f first
#define s second
using namespace std;
 
ll n, m, x, y, c, p;
vector<pll> v[100001];
unordered_map<ll, ll> cnt[100001], dist[100001];
priority_queue<pair<pll, ll>, vector<pair<pll, ll> >, greater<pair<pll, ll> > > pq;
 
void dij(ll st){
    for (pll i: v[st]){
        dist[st][i.s]=0;
        pq.push({{0, st}, i.s});
    }
    while (!pq.empty()){
        pll p=pq.top().f;
        ll color=pq.top().s;
        pq.pop();
        if (dist[p.s][abs(color)]!=p.f) continue;
        if (color<0) cnt[p.s][-color]--;
        for (pll i: v[p.s]){
            if (cnt[p.s][i.s]==1){
                if (dist[i.f][i.s]>p.f){
                    dist[i.f][i.s]=p.f;
                    pq.push({{p.f, i.f}, i.s});
                }
            }else{
                if (dist[i.f][i.s]>p.f+1){
                    dist[i.f][i.s]=p.f+1;
                    pq.push({{p.f+1, i.f}, -i.s});
                }
            }
        }
        if (color<0) cnt[p.s][-color]++;
    }
}
 
int main(){
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    cin >> n >> m;
    for (int i=1; i<=m; i++){
        cin >> x >> y >> c >> p;
        v[x].push_back({y, c});
        v[y].push_back({x, c});
        cnt[x][c]++, cnt[y][c]++;
        dist[x][c]=dist[y][c]=1e18;
    }
    dij(1);
    ll ans=1e18;
    for (pll i: v[n]) ans=min(ans, dist[n][i.s]);
    if (ans==1e18) cout << "-1\n";
    else cout << ans << "\n";
}

• Subtask 1: 0 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42