Submission #535672

#	Time	Username	Problem	Language	Result	Execution time	Memory
535672		Antekb	Sparklers (JOI17_sparklers)	C++14	0 / 100	1 ms	596 KiB

sparklers

#include<bits/stdc++.h>
using namespace std;
#define st first
#define nd second
typedef pair<int, int> pii;
const int N=1<<10;
bool czy=1;
pii seg[N];
vector<int> tab[N+N], tab2[N+N];
//int opt[3][N+N], opt2[3][N+N];
void insert(int id){
	int l=seg[id].st+N, r=seg[id].nd+1+N;
	for(;l<r; l>>=1, r>>=1){
		if(l&1)tab[l++].push_back(id);
		if(r&1)tab[--r].push_back(id);
	}
}
int vis[N];
void dfs(int s){
	vector<int> V;
	V.push_back(s);
	vis[s]=1;
	for(int i=0; i<V.size(); i++){
		int v=V[i];
		int l=seg[v].st+N, r=seg[v].nd+N;
		//cout<<v<<" "<<vis[v]<<"\n";
		while(l){
			while(tab[l].size()){
				int u=tab[l].back();
				//cout<<l<<" "<<v<<" "<<u<<"\n";
				if(seg[u].nd>seg[v].nd)break;
				if(!vis[u]){
					vis[u]=3-vis[v];
					V.push_back(u);
				}
				else if(vis[u]==vis[v])czy=0;
				tab[l].pop_back();
			}
			l/=2;
		}
		while(r){
			while(tab2[r].size()){
				int u=tab2[r].back();
				//cout<<r<<" "<<v<<" + "<<u<<"\n";
				if(seg[u].st<seg[v].st)break;
				if(!vis[u]){
					vis[u]=3-vis[v];
					V.push_back(u);
				}
				else if(vis[u]==vis[v])czy=0;
				tab2[r].pop_back();
			}
			r/=2;
		}
	}
}
//int lew[N], pra[N];
bool solve(vector<int> id){
	vector<pair<int, pii> > V;
	for(int i:id){
		V.push_back({seg[i].st, {1, i}});
		V.push_back({seg[i].nd, {-1, i}});
	}
	vector<int> V2;
	sort(V.begin(), V.end());
	for(int i=0; i<V.size(); i++){
		if(V[i].nd.st==1)V2.push_back(V[i].nd.nd);
		else{
			if(!V2.size() || V2.back()!=V[i].nd.nd)return 0;
			V2.pop_back();
		}
	}
	return 1;
}
int main(){
	ios_base::sync_with_stdio(0);cin.tie(0);
	int n;
	cin>>n;
	for(int i=0; i<n; i++){
		cin>>seg[i].st>>seg[i].nd;
		insert(i);
	}
	for(int i=1; i<N+N; i++){
		sort(tab[i].begin(), tab[i].end(), [](int a, int b){return seg[a].nd>seg[b].nd;});
		tab2[i]=tab[i];
		sort(tab2[i].begin(), tab2[i].end(), [](int a, int b){return seg[a].st<seg[b].st;});
		//cout<<i<<"a\n";
		//for(int j:tab[i])cout<<j<<" ";
		//cout<<"\n";
	}
	int ile=0, ans=1;
	int mod=1e9+7;
	/*vector<pii> V2;
	for(int i=0; i<n; i++){
		V2.push_back({seg[i].st-seg[i].nd, i});
	}
	sort(V2.begin(), V2.end());*/
	for(int i=0; i<n; i++){
		int j=i;
		if(!vis[j]){
			ile++;
			ans*=2;
			if(ans>=mod)ans-=mod;
			dfs(j);
		}
	}
	vector<int> V, V2;
	for(int i=0; i<n; i++){
		if(vis[i]==2)V.push_back(i);
		else V2.push_back(i);
	}
	czy=solve(V)&solve(V2);
	/*vector<pair<pii, int> > V;
	for(int i=0; i<n; i++){
		V.push_back({seg[i], i});
	}
	sort(V.begin(), V.end());
	set<int> S;
	for(int i=0; i<n; i++){
		int a=V[i].st.st, b=V[i].st.nd, c=V[i].nd;
		S.insert(b);
		auto it=S.find(b);
		if(it!=S.begin()){
			it--;
			lew[c]=*it;
		}
		else lew[c]=a;
	}
	S.clear();
	for(int i=0; i<n; i++)swap(V[i].st.st, V[i].st.nd);
	sort(V.begin(), V.end());
	for(int i=n-1; i>=0; i--){
		int a=V[i].st.st, b=V[i].st.nd, c=V[i].nd;
		//cerr<<a<<" "<<b<<" "<<c<<endl;
		S.insert(b);
		auto it=S.find(b);
		it++;
		if(b!=(*S.crend())){
			pra[c]=*it;
		}
		else pra[c]=a;
	}
	for(int i=0; i<n; i++){
		//cerr<<pra[i]<<" "<<lew[i]<<endl;
		if(pra[i]<lew[i])ans=0;
	}*/
	cout<<ans*czy;
}

Compilation message (stderr)

sparklers.cpp: In function 'void dfs(int)':
sparklers.cpp:23:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |  for(int i=0; i<V.size(); i++){
      |               ~^~~~~~~~~
sparklers.cpp: In function 'bool solve(std::vector<int>)':
sparklers.cpp:66:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |  for(int i=0; i<V.size(); i++){
      |               ~^~~~~~~~~

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 50