#include <bits/stdc++.h> //#include <windows.h> //#include <conio.h> #define N 1001001 #define M #define CODE "SLAMP" #define MOD #define MOD1 #define MOD2 #define F first #define S second #define pb push_back #define eb emplace_back #define is insert #define mkp make_pair typedef int ui; typedef long long ul; typedef long double ud; typedef std::pair<int,int> pii; typedef std::pair<long long,long long> pll; using namespace std; constexpr int iinf=(int)1e9+7; constexpr long long linf=(long long)1e18+7; ui n; pii p[N]; namespace Subtask_2 { bool check() { return n<=16; } vector<ui> ans; ui bin[N]; struct st { ui fst,lst,cnt; }row[N],col[N]; void reset() { ans.clear(); for(ui i=1;i<N;i++) { row[i].fst=0; row[i].lst=0; row[i].cnt=0; col[i].fst=0; col[i].lst=0; col[i].cnt=0; } } bool ok() { for(ui i=1;i<=n;i++) { if(row[p[i].F].cnt>2) return false; if(col[p[i].S].cnt>2) return false; bool n=true,d=true; if(p[i].F>col[p[i].S].lst || p[i].F<col[p[i].S].fst) n=false; if(p[i].S>row[p[i].F].lst || p[i].S<row[p[i].F].fst) d=false; if(!n && !d) return false; } return true; } void Try() { if((ui)ans.size()>0) return ; for(ui i=1;i<=16;i++) { row[i].fst=0; row[i].lst=0; row[i].cnt=0; col[i].fst=0; col[i].lst=0; col[i].cnt=0; } for(ui i=1;i<=n;i++) if(bin[i]) { row[p[i].F].cnt++; col[p[i].S].cnt++; if(row[p[i].F].fst==0 || row[p[i].F].fst>p[i].S) row[p[i].F].fst=p[i].S; if(row[p[i].F].lst<p[i].S) row[p[i].F].lst=p[i].S; if(col[p[i].S].fst==0 || col[p[i].S].fst>p[i].F) col[p[i].S].fst=p[i].F; if(col[p[i].S].lst<p[i].F) col[p[i].S].lst=p[i].F; } if(ok()) for(ui i=1;i<=n;i++) ans.pb(bin[i]); } void backtrack(ui pos) { if((ui)ans.size()>0) return ; for(ui i=0;i<2;i++) { bin[pos]=i; if(pos==n) Try(); else backtrack(pos+1); } } void solve() { reset(); backtrack(1); } void printAns() { for(ui i=0;i<(ui)ans.size();i++) cout<<ans[i]; cout<<"\n"; } } namespace Subtask_3 { bool check() { return true; } vector<ui> ans; pii high[N],low[N]; bool on[N]; void reset() { ans.clear(); memset(high,0,sizeof high); memset(low,0,sizeof low); memset(on,false,sizeof on); } void solve() { for(ui i=1;i<=n;i++) { if(low[p[i].S].S==0) low[p[i].S]={i,p[i].F}; else if(low[p[i].S].S>p[i].F) low[p[i].S]={i,p[i].F}; if(high[p[i].S].S<p[i].F) high[p[i].S]={i,p[i].F}; } for(ui i=1;i<=1000000;i++) if(high[i].S!=0 && low[i].S!=0) { on[high[i].F]=true; on[low[i].F]=true; } for(ui i=1;i<=n;i++) ans.pb(on[i]); } void printAns() { for(ui i=0;i<(ui)ans.size();i++) cout<<ans[i]; cout<<"\n"; } } int32_t main() { ios_base::sync_with_stdio(false); cin.tie(nullptr);cout.tie(nullptr); #ifdef CODE if(fopen(CODE".INP","r")) { freopen(CODE".INP","r",stdin); freopen(CODE".OUT","w",stdout); } #endif // CODE #define __FILE_CHECK__ #ifdef __FILE_CHECK__ if(fopen("inp.txt","r")) { freopen("inp.txt","r",stdin); freopen("out.txt","w",stdout); freopen("ans.txt","w",stderr); } #endif // __FILE_CHECK__ cin>>n; for(ui i=1;i<=n;i++) cin>>p[i].F>>p[i].S; if(Subtask_2::check()) { Subtask_2::solve(); Subtask_2::printAns(); } else { Subtask_3::solve(); Subtask_3::printAns(); } return 0; }

Main.cpp: In function 'int32_t main()':
Main.cpp:154:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  154 |         freopen(CODE".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:155:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  155 |         freopen(CODE".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:162:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  162 |        freopen("inp.txt","r",stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
Main.cpp:163:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  163 |        freopen("out.txt","w",stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:164:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  164 |        freopen("ans.txt","w",stderr);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~