#include<bits/stdc++.h> using namespace std; #define foru(i,a,b) for(int i=(a); i<=(b); ++i) #define ford(i,a,b) for(int i=(a); i>=(b); --i) #define rep(i,a) for(int i=0; i<(a); ++i) #define sz(a) (int)(a).size() #define all(a) (a).begin(),(a).end() #define bit(s,i) (((s)>>(i))&1) #define ii pair<int,int> #define vi vector<int> #define vii vector<ii> #define fi first #define se second #define ll long long #define eb emplace_back #define pb push_back #define __builtin_popcount __builtin_popcountll #define _ << " " << template <class X, class Y> bool maxi(X &x, Y y){return x<y?x=y,true:false;} template <class X, class Y> bool mini(X &x, Y y){return x>y?x=y,true:false;} const int N=1e6+5; int n,x[N],y[N]; vector<ii> iny[N]; int cntL[N],cntR[N]; set<ii> st[N]; vector<int> large; bool isLarge[N]; bool choose[N]; void solve(){ cin>>n; foru(i,1,n){ cin>>x[i]>>y[i]; iny[y[i]].eb(x[i],i); } foru(i,1,N-1) if(!iny[i].empty()){ sort(all(iny[i])); cntL[i]=0; cntR[i]=sz(iny[i])-1; st[iny[i][cntL[i]].fi].insert(ii(i,cntL[i])); if(sz(iny[i])>=2) st[iny[i][cntR[i]].fi].insert(ii(i,cntR[i])); } foru(i,1,N-1){ if(sz(st[i])>2) large.eb(i), isLarge[i]=true; } while(!large.empty()){ int x=large.back(); large.pop_back(); isLarge[x]=0; assert(sz(st[x])>2); auto it=st[x].begin(); ++it; while(it!=prev(st[x].end())){ int y=it->fi; if(it->se==cntL[y]){ if(cntL[y]+1<cntR[y]){ int nxtx=iny[y][cntL[y]+1].fi; st[nxtx].insert(ii(y,cntL[y]+1)); if(sz(st[nxtx])>2 && !isLarge[nxtx]){ isLarge[nxtx]=1; large.eb(nxtx); } } ++cntL[y]; } else if(it->se==cntR[y]){ if(cntR[y]-1>cntL[y]){ int prvx=iny[y][cntR[y]-1].fi; st[prvx].insert(ii(y,cntR[y]-1)); if(sz(st[prvx])>2 && !isLarge[prvx]){ isLarge[prvx]=1; large.eb(prvx); } } --cntR[y]; } else{ assert(0); } it=st[x].erase(it); } } foru(i,1,N-1) if(!iny[i].empty()){ if(cntL[i]<cntR[i]){ choose[iny[i][cntL[i]].se]=1; choose[iny[i][cntR[i]].se]=1; } else if(cntL[i]==cntR[i]){ choose[iny[i][cntR[i]].se]=1; } } foru(i,1,n) cout<<choose[i]; } int32_t main(){ #define task "test" if(fopen(task".inp", "r")){ freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); } cin.tie(0)->sync_with_stdio(0); int tc=1; //cin>>tc; foru(i,1,tc){ solve(); } }

Main.cpp: In function 'int32_t main()':
Main.cpp:105:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:106:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~