Submission #855951

#	Time	Username	Problem	Language	Result	Execution time	Memory
855951		phoenix0423	Commuter Pass (JOI18_commuter_pass)	C++17	100 / 100	350 ms	29160 KiB

commuter_pass

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll, ll> pll;
#define fastio ios::sync_with_stdio(false), cin.tie(0)
#define pb push_back
#define eb emplace_back
const int maxn = 2e5 + 5;
const int N = 1e9 + 7;
const ll INF = 1e18;
vector<pll> adj[maxn];
int n, m, s, t, u, v;
ll dist[maxn][6];

void dijkstra(int st, int id){
	for(int i = 0; i < n; i++) dist[i][id] = INF;
	dist[st][id] = 0;
	priority_queue<pll, vector<pll>, greater<pll>> q;
	q.push({0, st});
	while(!q.empty()){
		auto [d, pos] = q.top(); q.pop();
		if(dist[pos][id] != d) continue;
		for(auto [x, w] : adj[pos]){
			if(dist[x][id] > dist[pos][id] + w){
				dist[x][id] = dist[pos][id] + w;
				q.push({dist[x][id], x});
			}
		}
	}
}

void dijkstra2(int dir, int id){
	priority_queue<pll, vector<pll>, greater<pll>> q;
	for(int i = 0; i < n; i++) dist[i][id] = dist[i][2], q.push({dist[i][id], i});
	while(!q.empty()){
		auto [d, pos] = q.top(); q.pop();
		if(dist[pos][id] != d) continue;
		for(auto [x, w] : adj[pos]){
			if(dist[pos][dir] + dist[x][dir ^ 1] + w == dist[t][0]){
				if(dist[x][id] > dist[pos][id]){
					dist[x][id] = dist[pos][id];
					q.push({dist[x][id], x});
				}
			}
		}
	}
}

int main(void){
	fastio;
	cin>>n>>m>>s>>t>>u>>v;
	s--, t--, u--, v--;
	for(int i = 0; i < m; i++){
		int a, b, c;
		cin>>a>>b>>c;
		a--, b--;
		adj[a].eb(b, c);
		adj[b].eb(a, c);
	}
	dijkstra(s, 0);
	dijkstra(t, 1);
	dijkstra(v, 2);
	dijkstra2(0, 3);
	dijkstra2(1, 4);
	dijkstra(u, 5);
	ll ans = INF;
	for(int i = 0; i < n; i++) ans = min(ans, dist[i][5] + min(dist[i][3], dist[i][4]));
	cout<<ans<<"\n";
}

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