Submission #45655

#	Time	Username	Problem	Language	Result	Execution time	Memory
45655		reality	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	839 ms	52180 KiB

commuter_pass

#include "bits/stdc++.h"
using namespace std;
#define fi first
#define se second
#define ll long long
#define dbg(v) cerr<<#v<<" = "<<v<<'\n'
#define vi vector<int>
#define vl vector <ll>
#define pii pair<int,int>
#define mp make_pair
#define db long double
#define pb push_back
#define all(s) s.begin(),s.end()
template < class T > T smin(T &a,T b) {if (a > b) a = b;return a;}
template < class T > T smax(T &a,T b) {if (a < b) a = b;return a;}
const int N = (int)(1e6) + 5;
ll D1[N];
ll D2[N];
ll D3[N];
ll D4[N];
vector < pii > g[N];
int n;
void Go(ll D[],int S) {
	for (int i = 1;i <= n;++i)
		D[i] = 1e18;
	D[S] = 0;
	priority_queue < pair < ll , int > , vector < pair < ll , int > > , greater < pair < ll , int > > > Q;
	Q.push(mp(0,S));
	while (!Q.empty()) {
		const ll cost = Q.top().fi;
		const int node = Q.top().se;
		Q.pop();
		if (cost != D[node])
			continue;
		for (auto it : g[node])
			if (D[it.fi] > D[node] + it.se)
				D[it.fi] = D[node] + it.se,Q.push(mp(D[it.fi],it.fi));
	}
}
int was[N];
ll d1[N];
ll d2[N];
int main(void)
{
    int m;
    int S,T,U,V;
    cin>>n>>m>>S>>T>>U>>V;
    while (m --) {
    	int a,b,c;
    	cin>>a>>b>>c;
    	g[a].pb(mp(b,c));
    	g[b].pb(mp(a,c));
    }
    Go(D1,S);
    Go(D2,T);
    Go(D3,U);
    Go(D4,V);
    vi points;
    const ll dist = D1[T];
    for (int i = 1;i <= n;++i)
    	if (D1[i] + D2[i] == dist)
    		points.pb(i);
    ll ans = D3[V];
    sort(all(points),[&](int x,int y) {
    		return D1[x] < D1[y];
    	});
    for (auto it : points) {
    	d1[it] = D3[it];
    	d2[it] = D4[it];
    	for (auto edge : g[it]) {
    		if (D1[edge.fi] + edge.se + D2[it] == dist)
    			smin(d1[it],d1[edge.fi]),smin(d2[it],d2[edge.fi]);
    	}
    	smin(ans,d1[it] + D4[it]);
    	smin(ans,d2[it] + D3[it]);
    }
    cout << ans << '\n';
    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 45 / 45