제출 #638883

#제출 시각아이디문제언어결과실행 시간메모리
638883MohamedAhmed04Evacuation plan (IZhO18_plan)C++14
100 / 100
531 ms45028 KiB
#include <bits/stdc++.h>

using namespace std ;

const int MAX = 1e5 + 10 ;

int arr[MAX] ;
int n , m , k , q ;

vector< vector< pair<int , int> > >adj(MAX) ;

vector< pair<int , int> >queries[MAX] ;

int dist[MAX] ;

void dijkstra()
{
	for(int i = 1 ; i <= n ; ++i)
		dist[i] = 1e9 ;
	priority_queue< pair<int , int> , vector< pair<int , int> > , greater< pair<int , int> > >q ;
	for(int i = 0 ; i < k ; ++i)
		dist[arr[i]] = 0 , q.push({0 , arr[i]}) ;
	while(!q.empty())
	{
		pair<int , int>p = q.top() ;
		q.pop() ;
		int node = p.second , cost = p.first ;
		if(dist[node] < cost)
			continue ;
		for(auto &child : adj[node])
		{
			int child2 = child.first ;
			int cost2 = cost + child.second ;
			if(cost2 < dist[child2])
			{
				dist[child2] = cost2 ;
				q.push({cost2 , child2}) ;
			}
		}
	}
}

vector<int>v[MAX] ;
int par[MAX] , sz[MAX] , ans[MAX] ;

void init()
{
	for(int i = 1 ; i <= n ; ++i)
		par[i] = i , sz[i] = 1 , v[i].push_back(i) ;
}

int root(int node)
{
	if(par[node] == node)
		return node ;
	return (par[node] = root(par[node])) ;
}

void Union(int x , int y , int z)
{
	int a = root(x) ;
	int b = root(y) ;
	if(a == b)
		return ;
	if(sz[a] < sz[b])
		swap(a , b) ;
	while(v[b].size())
	{
		int node = v[b].back() ;
		for(auto &p : queries[node])
		{
			int node2 = p.first , idx = p.second ;
			if(root(node2) == a)
				ans[idx] = z ;
		}
		v[a].push_back(node) ;
		v[b].pop_back() ;
	}
	par[b] = a ;
	sz[a] += sz[b] ;
}

int main()
{
	ios_base::sync_with_stdio(0) ;
	cin.tie(0) ;
	cin>>n>>m ;
	for(int i = 0 ; i < m ; ++i)
	{
		int x , y , z ;
		cin>>x>>y>>z ;
		adj[x].emplace_back(y , z) ;
		adj[y].emplace_back(x , z) ;
	}
	cin>>k ;
	for(int i = 0 ; i < k ; ++i)
		cin>>arr[i] ;
	cin>>q ;
	for(int i = 0 ; i < q ; ++i)
	{
		int x , y ;
		cin>>x>>y ;
		queries[x].emplace_back(y , i) ;
		queries[y].emplace_back(x , i) ;
	}
	dijkstra() ;
	vector< array<int , 3> >edges ;
	for(int i = 1 ; i <= n ; ++i)
	{
		for(auto &child : adj[i])
		{
			if(child.first > i)
				edges.push_back({min(dist[i] , dist[child.first]) , i , child.first}) ;
		}
	}
	sort(edges.begin() , edges.end()) ;
	reverse(edges.begin() , edges.end()) ;
	init() ;
	for(auto &a : edges)
	{
		int x = a[1] , y = a[2] , z = a[0] ;
		Union(x , y , z) ;
	}
	for(int i = 0 ; i < q ; ++i)
		cout<<ans[i]<<"\n" ;
	return 0 ;
}		
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