#include "bits/stdc++.h" using namespace std; #define task "SLAMP" #define ll long long #define endl '\n' #define x first #define y second #define vall(a) (a).begin(), (a).end() #define sze(a) (int)a.size() #define pii pair<int, int> #define pll pair<ll, ll> #define ep emplace_back #define pb push_back #define pf push_front const ll mod = 1e9 + 7; const int N = 2e6 + 5; const ll oo = 1e18; int n, m; pii a[N]; vector<int> arr; namespace sub2 { int ans[N], b[N]; vector<int> sadx[N], sady[N]; bool kt() { for (int i = 0; i < m; ++i) { sadx[i].clear(); sady[i].clear(); } for (int i = 1; i <= n; ++i) { if (b[i]) { sadx[a[i].x].pb(a[i].y); sady[a[i].y].pb(a[i].x); } } for (int i = 0; i < m; ++i) { if (sze(sadx[i]) > 2 || sze(sady[i]) > 2) return false; sort(vall(sadx[i])); sort(vall(sady[i])); } for (int i = 1; i <= n; ++i) { bool flag = false; auto it1 = lower_bound(vall(sadx[a[i].x]), a[i].y); auto it2 = upper_bound(vall(sadx[a[i].x]), a[i].y); if (it1 != sadx[a[i].x].end() && it2 != sadx[a[i].x].begin()) flag = true; it1 = lower_bound(vall(sady[a[i].y]), a[i].x); it2 = upper_bound(vall(sady[a[i].y]), a[i].x); if (it1 != sady[a[i].y].end() && it2 != sady[a[i].y].begin()) flag = true; if (!flag) return false; } for (int i = 1; i <= n; ++i) ans[i] = b[i]; return true; } bool bt(int i) { if (i == n + 1) return kt(); b[i] = 0; if (bt(i + 1)) return true; b[i] = 1; if (bt(i + 1)) return true; return false; } void solve() { bt(1); for (int i = 1; i <= n; ++i) cout << ans[i]; } bool check() { return n <= 20; } } namespace sub3 { bool ans[N]; vector<pii> sad[N]; void solve() { for (int i = 1; i <= n; ++i) sad[a[i].y].pb(make_pair(a[i].x, i)); for (int i = 0; i < m; ++i) { if (!sad[i].empty()) { ans[sad[i].back().y] = true; ans[sad[i][0].y] = true; } } for (int i = 1; i <= n; ++i) cout << ans[i]; } } inline void solve() { sort(vall(arr)); arr.erase(unique(vall(arr))); for (int i = 1; i <= n; ++i) { a[i].x = lower_bound(vall(arr), a[i].x) - arr.begin(); a[i].y = lower_bound(vall(arr), a[i].y) - arr.begin(); } m = sze(arr); if (sub2::check()) return sub2::solve(); return sub3::solve(); } inline void input() { cin >> n; for (int i = 1; i <= n; ++i) { cin >> a[i].x >> a[i].y; arr.pb(a[i].x); arr.pb(a[i].y); } return solve(); } int main() { if(fopen(task ".inp", "r")) { freopen(task ".inp", "r", stdin); freopen(task ".out", "w", stdout); } ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); input(); return 0; } //2911

Main.cpp: In function 'int main()':
Main.cpp:138:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  138 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:139:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~