Submission #287831

#	Time	Username	Problem	Language	Result	Execution time	Memory
287831		nandonathaniel	Evacuation plan (IZhO18_plan)	C++14	100 / 100	1106 ms	55536 KiB

plan

#include<bits/stdc++.h>
using namespace std;
const int MAXN=100005,INF=1e9;
typedef pair<int,int> pii;
vector<pii> adj[MAXN],query[MAXN];
int dist[MAXN],ans[MAXN],par[MAXN],a[MAXN],b[MAXN],lo[MAXN],hi[MAXN];
bool udah[MAXN];
pair<int,pii> arr[5*MAXN];
vector<int> mid[5*MAXN];

int find(int x){
	if(par[x]==x)return par[x];
	return par[x]=find(par[x]);
}

void join(int a,int b){
	int ortua=find(a),ortub=find(b);
	par[ortua]=ortub;
}

int main(){
	ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	int n,m,u,v,w,k,q;
	cin >> n >> m;
	for(int i=1;i<=m;i++){
		cin >> u >> v >> w;
		adj[u].push_back({v,w});
		adj[v].push_back({u,w});
	}
	cin >> k;
	for(int i=1;i<=n;i++){
		dist[i]=INF;
	}
	priority_queue<pii,vector<pii>,greater<pii> > PQ;
	for(int i=1;i<=k;i++){
		cin >> u;
		dist[u]=0;
		PQ.push({0,u});
	}
	while(!PQ.empty()){
		pii now=PQ.top();
		PQ.pop();
		if(dist[now.second]<now.first)continue;
		for(auto nxt : adj[now.second]){
			if(dist[now.second]+nxt.second<dist[nxt.first]){
				dist[nxt.first]=dist[now.second]+nxt.second;
				PQ.push({dist[nxt.first],nxt.first});
			}
		}
	}
	int no=0;
	for(int i=1;i<=n;i++){
		for(auto nxt : adj[i]){
			if(i>nxt.first)continue;
			no++;
			arr[no]={min(dist[i],dist[nxt.first]),{i,nxt.first}};
		}
	}
	sort(arr+1,arr+m+1);
	cin >> q;
	for(int i=1;i<=q;i++){
		cin >> a[i] >> b[i];
		lo[i]=1;hi[i]=m;
		mid[(lo[i]+hi[i])/2].push_back(i);
	}
	bool masih=1;
	while(masih){
		masih=0;
		for(int i=1;i<=n;i++)par[i]=i;
		for(int i=m;i>=1;i--){
			join(arr[i].second.first,arr[i].second.second);
			while(!mid[i].empty()){
				int last=mid[i].back();
				mid[i].pop_back();
				if(find(a[last])==find(b[last])){
					lo[last]=i+1;
					ans[last]=arr[i].first;
				}
				else hi[last]=i-1;
				if(lo[last]<=hi[last]){
					mid[(lo[last]+hi[last])/2].push_back(last);
					masih=1;
				}
			}
		}
	}
	for(int i=1;i<=q;i++)cout << ans[i] << '\n';
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 12 / 12
• Subtask 4: 19 / 19
• Subtask 5: 46 / 46