#include <bits/stdc++.h> using namespace std; using ll = long long; #define int long long #define pii pair<ll, ll> #define fi first #define se second const ll N = 1e6 + 5, inf = 1e9, mod = 1e9 + 7, block = 320, lim = 20; int n; pii a[N]; string convert(int x) { string s = ""; while(x > 0) { int val = x % 2; s += to_string(val); x /= 2; } reverse(s.begin(), s.end()); return s; } int reconvert(string s) { reverse(s.begin(), s.end()); int tt = 0; for (int i = 0; i < s.size(); i++) { int val = s[i] - '0'; tt += val * (1ll << i); } return tt; } namespace sub1 { map <int, int> cnt1, cnt2; // hang, cot int cal(int mask) { cnt1.clear(), cnt2.clear(); for (int i = 0; i < n; i++) { if ((mask >> i) & 1) { cnt1[a[i].fi]++, cnt2[a[i].se]++; if (cnt1[a[i].fi] > 2 || cnt2[a[i].se] > 2) return 0; } } for (int i = 0; i < n; i++) { if ((mask >> i) & 1) continue; else { int okL = 0, okR = 0; for (int j = 0; j < n; j++) { // xet 2 hang ngang if ((mask >> j) & 1) { if (a[j].fi == a[i].fi && a[j].se < a[i].se) okL = 1; if (a[j].fi == a[i].fi && a[j].se > a[i].se) okR = 1; } } if (okL && okR) continue; int okU = 0, okD = 0; for (int j = 0; j < n; j++) { // xet 2 hang doc if ((mask >> j) & 1) { if (a[j].se == a[i].se && a[j].fi < a[i].fi) okU = 1; if (a[j].se == a[i].se && a[j].fi > a[i].fi) okD = 1; } } if (okU && okD) continue; return 0; } } return 1; } void solve() { // cout << reconvert("101010101") << '\n'; for (int mask = 0; mask < (1 << n); mask++) { // cout << mask << '\n'; // if (mask == 341) cout << cal(mask) << '\n'; if (cal(mask)) { for (int i = 0; i < n; i++) { if ((mask >> i) & 1) cout << 1; else cout << 0; } return; } } } } namespace sub2 { vector <pii> pre[N]; int On[N]; void solve() { // for qua tat ca cac cot vector <int> comp; for (int i = 0; i < n; i++) { pre[a[i].se].emplace_back(a[i].fi, i); comp.push_back(a[i].se); } sort(comp.begin(), comp.end()); comp.erase(unique(comp.begin(), comp.end()), comp.end()); for (int i = 0; i < comp.size(); i++) { int idx = comp[i]; sort(pre[idx].begin(), pre[idx].end()); } for (int i = 0; i < comp.size(); i++) { int idx = comp[i]; if (pre[idx].size() == 1) { On[pre[idx].back().se] = 1; continue; } else { int L = pre[idx][0].se; int R = pre[idx].back().se; On[L] = 1, On[R] = 1; continue; } } for (int i = 0; i < n; i++) cout << On[i]; } } signed main() { ios::sync_with_stdio(false); cin.tie(0); if (fopen("slamp.inp", "r")) { freopen("slamp.inp", "r", stdin); freopen("slamp.out", "w", stdout); } cin >> n; for (int i = 0; i < n; i++) cin >> a[i].fi >> a[i].se; // sub2::solve(); return 0; if (n <= 16) { sub1::solve(); } else sub2::solve(); return 0; }

Main.cpp: In function 'int main()':
Main.cpp:122:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |         freopen("slamp.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:123:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  123 |         freopen("slamp.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~