Submission #1086851

#	Time	Username	Problem	Language	Result	Execution time	Memory
1086851		peacebringer1667	Commuter Pass (JOI18_commuter_pass)	C++17	31 / 100	190 ms	19872 KiB

commuter_pass

#include<bits/stdc++.h>
#define ll long long
#define ldb long double
#define fi first
#define se second
#define sza(a) (int)a.size()
#define pir pair<int,int>
#define pirll pair<ll,int>
using namespace std;
const int maxn = 1e5 + 5;
 
ll dist[maxn][3],D = 0,dp[maxn];
bool mark[maxn];
vector <vector<pir>> vec(maxn);
 
void input(int n,int m){
	while (m--){
		int u,v,w;
		cin >> u >> v >> w;
		vec[u].push_back({v,w});
		vec[v].push_back({u,w});
	}
}
 
void dijkstra(int source,int n,int st){
	for (int i = 1 ; i <= n ; i++) mark[i] = 0;
	priority_queue <pirll,vector<pirll>,greater<pirll>> pq;
	pq.push({0,source});
	
	while (pq.size()){
		pirll t = pq.top();
		pq.pop();
		
		int u = t.se;ll w = t.fi;
		if (mark[u]) continue;
		mark[u] = 1;
		dist[u][st] = w;
		
		for (pir v : vec[u])
		  if (!mark[v.fi])
		    pq.push({v.se + w,v.fi});
	}
	
	D = dist[source][0];
}
 
void solve(int source,int n){
	for (int i = 1 ; i <= n ; i++)
		mark[i] = 0;
	priority_queue <pirll,vector<pirll>,greater<pirll>> pq;
	pq.push({0,source});
	
	while (pq.size()){
		pirll t = pq.top();
		pq.pop();
		
		int u = t.se;ll w = t.fi;
		if (mark[u]) continue;
		mark[u] = 1;
		dp[u] = w;
		
		for (pir node : vec[u])
		  if (!mark[node.fi]){
		  	int v = node.fi,e = node.se;
		  	
		  	if (dist[u][0] + e + dist[v][1] == D || dist[u][1] + e + dist[v][0] == D)
		  	  pq.push({w,v});
		  	else
		  	  pq.push({w + e,v});
		  }
	}
}
 
int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	//freopen("commuterpass.inp","r",stdin);
//	freopen("commuterpass.out","w",stdout);
	int n,m,S,T,U,V;
	cin >> n >> m >> S >> T >> U >> V;
	input(n,m);
	dijkstra(S,n,0);
	dijkstra(T,n,1);
	
	solve(U,n);
	cout << dp[V];
 
	return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45