Submission #532816

#	Time	Username	Problem	Language	Result	Execution time	Memory
532816		couplefire	Port Facility (JOI17_port_facility)	C++17	100 / 100	1475 ms	182968 KiB

port_facility

#include <bits/stdc++.h>
using namespace std;
#define ll long long

const int N = 1e6+15,mod = 1e9+7;

int L[N],R[N];
 
int par[N],enemy[N];
 
int find(int a){
	if(a==-1)return -1;
	if(a==par[a])return a;
	return par[a]= find(par[a]);
}
 
set<int> dsuid[N];
set<pair<int,int> >minid;
int sz[N];
 
void push(int x,int y){
 
	minid.erase(make_pair(*dsuid[y].begin(),y));
	minid.erase(make_pair(*dsuid[x].begin(),x));
	while(dsuid[y].size()>0){
		dsuid[x].insert(*dsuid[y].begin());
		dsuid[y].erase(dsuid[y].begin());
	}
	minid.insert(make_pair(*dsuid[x].begin(),x) );
}
void make(int v,int a){
	if(v!=-1 && sz[v]>sz[a]){
		par[a]= v;
		sz[v]+=sz[a];
		push(v,a);
	}
	else if(v!=-1){
		par[v]= a;
		sz[a]+=sz[v];
		push(a,v);
	}
}
void make_enemy(int a,int b){
 
	a = find(a),b = find(b);
	int u = find(enemy[a]), v = find(enemy[b]);
	if(a==b || (u!=-1 && u==v)){
		printf("0\n");
		exit(0);
	}
	make(v,a);
	make(u,b);
	enemy[a]= b;
	enemy[b]= a;
}
 
int main(){
    int n;
    cin>>n;
    vector<pair<int,int> >v;
    for(int i=1;i<=n;++i){
    	scanf("%d%d",&L[i],&R[i]);
    	v.push_back(make_pair(L[i],i));
    }
    sort(v.begin(),v.end());
    for(int i=1;i<=n;++i){
    	par[i]= i,enemy[i]= -1,sz[i]= 1;
    	dsuid[i].insert(R[i]);
    }
 
   	set<pair<int,int> >s;
   	set<pair<int,int> >::iterator it,jt;
   	
   	set<int>::iterator nx;
 
   	int u;
	for(int i=0;i<v.size();++i){
 
		int l = v[i].first, id = v[i].second;
 
		while(minid.size()>0){
			it = minid.begin();
 
			if((*it).first>l)break;
 
 
			u = (*it).second;
			minid.erase(it);
			
			while(dsuid[u].size()>0){
				if( *dsuid[u].begin()>l)break;
				else
					dsuid[u].erase(dsuid[u].begin());
			}
			if(dsuid[u].size()>0)
				minid.insert(make_pair(*dsuid[u].begin(),u));
		}
 
		minid.insert(make_pair(R[id],id));
 
		vector<int> Q;
		for(it = minid.begin();it!= minid.end();++it){
			
			if( (*it).first>=R[id])break;
			Q.push_back((*it).second);
		}
 
		while(!Q.empty()){
			make_enemy(Q.back(),id);
			Q.pop_back();
		}
	}
	long long ret= 1;
	for(int i=1;i<=n;++i){
		if(find(i)==i&& find(enemy[i])<i){
			ret= (ret*2)%mod;
		}
	}
	cout<<ret<<endl;
 
    return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:77:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   77 |  for(int i=0;i<v.size();++i){
      |              ~^~~~~~~~~
port_facility.cpp:62:11: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   62 |      scanf("%d%d",&L[i],&R[i]);
      |      ~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 56 / 56
• Subtask 4: 22 / 22