#include <bits/stdc++.h> #define task "slamp" #define ll long long #define multitest 0 using namespace std; struct Point { int x, y; }; const int N = 1e6; int n; Point p[N+5]; bool ans[N+5]; int cntx[N+5], cnty[N+5]; vector<int> dx, dy, X[N+5], Y[N+5]; bool cmpx(int x, int y) { return p[x].x < p[y].x; } bool cmpy(int x, int y) { return p[x].y < p[y].y; } void on(int i) { if (ans[i]) return; cntx[p[i].x]++; cnty[p[i].y]++; ans[i] = 1; } void off(int i) { if (!ans[i]) return; cntx[p[i].x]--; cnty[p[i].y]--; ans[i] = 0; } namespace sub12 { const int sN = 16; bool vis[sN+5]; bool check() { return n <= sN; } void solve() { for (int msk = 0; msk < (1<<n); msk++) { for (auto x : dx) cntx[x] = 0; for (auto y : dy) cnty[y] = 0; fill(ans+1, ans+n+1, 0); for (int i = 0; i < n; i++) { if ((msk>>i)&1) on(i+1); } bool check = 1; for (auto x : dx) { check &= cntx[x] <= 2; } for (auto y : dy) { check &= cnty[y] <= 2; } if (!check) continue; fill(vis+1, vis+n+1, 0); for (auto x : dx) { int lf = -1, rt = -1; for (int i = 0; i < X[x].size() && lf < 0; i++) { if (ans[X[x][i]]) lf = i; } for (int i = X[x].size()-1; i >= 0 && rt < 0; i--) { if (ans[X[x][i]]) rt = i; } if (lf == -1) continue; for (int i = lf; i <= rt; i++) vis[X[x][i]] = 1; } for (auto y : dy) { int lf = -1, rt = -1; for (int i = 0; i < Y[y].size() && lf < 0; i++) { if (ans[Y[y][i]]) lf = i; } for (int i = Y[y].size()-1; i >= 0 && rt < 0; i--) { if (ans[Y[y][i]]) rt = i; } if (lf == -1) continue; for (int i = lf; i <= rt; i++) vis[Y[y][i]] = 1; } for (int i = 1; i <= n; i++) { check &= vis[i]; } if (!check) continue; break; } } } namespace sub3456 { void solve() { for (auto x : dx) { on(X[x][0]), on(X[x].back()); } for (auto y : dy) { on(Y[y][0]), on(Y[y].back()); } for (auto x : dx) { for (int i = 0; i < X[x].size(); i++) { if (cnty[p[X[x][i]].y] <= 2) break; if (X[x][i] == Y[p[X[x][i]].y][0] || X[x][i] == Y[p[X[x][i]].y].back()) continue; off(X[x][i]); if (i+1 < X[x].size()) { on(X[x][i+1]); } } for (int i = X[x].size()-1; i >= 0; i--) { if (cnty[p[X[x][i]].y] <= 2) break; if (X[x][i] == Y[p[X[x][i]].y][0] || X[x][i] == Y[p[X[x][i]].y].back()) continue; off(X[x][i]); if (i > 0) { on(X[x][i-1]); } } } for (auto y : dy) { for (int i = 0; i < Y[y].size(); i++) { if (cntx[p[Y[y][i]].x] <= 2) break; if (Y[y][i] == X[p[Y[y][i]].x][0] || Y[y][i] == X[p[Y[y][i]].x].back()) continue; off(Y[y][i]); if (i+1 < Y[y].size()) { on(Y[y][i+1]); } } for (int i = Y[y].size()-1; i >= 0; i--) { if (cntx[p[Y[y][i]].x] <= 2) break; if (Y[y][i] == X[p[Y[y][i]].x][0] || Y[y][i] == X[p[Y[y][i]].x].back()) continue; off(Y[y][i]); if (i > 0) { on(Y[y][i-1]); } } } } } void flo(int ID) { cin >> n; for (int i = 1; i <= n; i++) { cin >> p[i].x >> p[i].y; dx.push_back(p[i].x); dy.push_back(p[i].y); X[p[i].x].push_back(i); Y[p[i].y].push_back(i); } sort(dx.begin(), dx.end()); sort(dy.begin(), dy.end()); dx.resize(unique(dx.begin(), dx.end())-dx.begin()); dy.resize(unique(dy.begin(), dy.end())-dy.begin()); for (auto x : dx) { sort(X[x].begin(), X[x].end(), cmpy); } for (auto y : dy) { sort(Y[y].begin(), Y[y].end(), cmpx); } if (sub12::check()) sub12::solve(); else sub3456::solve(); for (int i = 1; i <= n; i++) cout << ans[i]; cout << "\n"; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); if (fopen(task".inp", "r")) { freopen(task".inp", "r", stdin); freopen(task".out", "w", stdout); } int TCS = 1, ID = 1; if (multitest) { cin >> TCS; } while (TCS--) flo(ID++); return 0; }

Main.cpp: In function 'int main()':
Main.cpp:230:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  230 |                 freopen(task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:231:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  231 |                 freopen(task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~