Submission #44657

#	Time	Username	Problem	Language	Result	Execution time	Memory
44657		ffresh	Port Facility (JOI17_port_facility)	C++17	0 / 100	47 ms	47356 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]);
}
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);
	}
	if(v!=-1)par[v]= a;
	if(u!=-1)par[u]= b;
	enemy[a]= b;
	enemy[b]= a;
}

set<int> dsuid[N]; 
int main(){

    //freopen("input.txt","r",stdin);
    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;

    	dsuid[i].insert(R[i]);
    }
 
   	set<pair<int,int> >s;
   	set<pair<int,int> >::iterator it,jt;
   	

   	set<pair<int,int> >minid;
   	
   	vector<pair<int,int> > temp;
   	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));
		}
		temp.clear();

		u = -1;
		for(it =minid.begin();it!= minid.end();){
			if( (*it).first>=R[id])break;
			jt = it;
			u = (*it).second;
			temp.push_back(*it);
			make_enemy(id,u);
			it = ++jt;
		}
		u = find(u);

		for(int j=0;j<temp.size();++j){
			pair<int,int> val = temp[j];
			if(val.second == u)continue;

			int v= val.second;
			minid.erase(val);

			while(!dsuid[v].empty()){
				dsuid[u].insert(*dsuid[v].begin());
				dsuid[v].erase(dsuid[v].begin());
			}
		}
		if(find(id)==id){
			minid.insert(make_pair(R[id],id));
		}
	}
	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:61:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<v.size();++i){
              ~^~~~~~~~~
port_facility.cpp:95:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<temp.size();++j){
               ~^~~~~~~~~~~~
port_facility.cpp:40:11: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
      scanf("%d%d",&L[i],&R[i]);
      ~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22