#include <bits/stdc++.h> using namespace std ; typedef long long ll ; typedef long double ld ; typedef pair<int, int> pii ; typedef pair<int, long long> pil ; typedef pair<long long, int> pli ; typedef pair<long long, long long> pll ; #define bitc(n) (__builtin_popcountll(n)) #define clz(n) (__builtin_clzll(n)) #define ctz(n) (__builtin_ctzll(n)) #define lgi(n) (31 - __builtin_clz(n)) #define lgl(n) (63 - __builtin_clzll(n)) #define MASK(k) (1ll << (k)) #define getbit(n, k) ((n) >> (k) & 1) #define flipbit(n, k) ((n) ^ (1ll << (k))) #define ton(n, k) ((n) | (1ll << (k))) #define toff(n, k) ((n) & ~(1ll << (k))) #define fi first #define se second #define mp make_pair #define eb emplace_back #define lwb lower_bound #define upb upper_bound #define sz(x) (int)(x.size()) #define all(x) x.begin(),x.end() #define taskname "slamp" template<class X, class Y> bool maximize(X &x, const Y &y) { if(x < y) { return x = y, true ; } return false ; } template<class X, class Y> bool minimize(X &x, const Y &y) { if(x > y) { return x = y, true ; } return false ; } template<class X> void removeDup(vector<X> &ve) { sort(ve.begin(), ve.end()) ; ve.resize(unique(ve.begin(), ve.end()) - ve.begin()) ; } const ll INF = 1e18 ; const int inf = 1e9 ; const int mod = 1e9 + 7 ; const int N = 1e6 + 5, LG = 17 ; /* Some Peach Tea Is Great ;-; */ /* Author : Tuandq */ int n ; pii a[N] ; namespace sub6 { vector<pii> tr[N], tc[N] ; deque<pii> row[N], col[N] ; int maskRow[N], maskCol[N], le, ri, up, dw ; bitset<N> mark ; void upset(const int &idx, int c, int r) { mark.set(idx) ; maskRow[a[idx].se] |= r ; maskCol[a[idx].fi] |= c ; } bool makeCol(int idx, const int &d) { if(col[idx].empty() || maskCol[idx] == 3) return false ; deque<pii> &ve = col[idx] ; while(!ve.empty() && (ve.back().fi > up || maskRow[ve.back().fi] == 3)) maskRow[ve.back().fi] |= d, ve.pop_back() ; while(!ve.empty() && (ve.front().fi < dw || maskRow[ve.front().fi] == 3)) maskRow[ve.front().fi] |= d, ve.pop_front() ; return !ve.empty() ; } bool makeRow(int idx, const int &d) { if(row[idx].empty() || maskRow[idx] == 3) return false ; deque<pii> &ve = row[idx] ; while(!ve.empty() && (ve.back().fi > ri || maskCol[ve.back().fi] == 3)) maskCol[ve.back().fi] |= d, ve.pop_back() ; while(!ve.empty() && (ve.front().fi < le || maskCol[ve.front().fi] == 3)) maskCol[ve.front().fi] |= d, ve.pop_front() ; return !ve.empty() ; } void solve() { for(int i = 1; i <= n; i ++) { tc[a[i].fi].emplace_back(a[i].se, i) ; tr[a[i].se].emplace_back(a[i].fi, i) ; } for(int i = 1; i < N; i ++) { sort(all(tr[i])) ; sort(all(tc[i])) ; if(!tr[i].empty()) for(pii cur : tr[i]) row[i].emplace_back(cur) ; if(!tc[i].empty()) for(pii cur : tc[i]) col[i].emplace_back(cur) ; } le = 1, ri = N - 1, up = N - 1, dw = 1 ; while(true) { while(true) { bool flag = false ; while(le <= ri && !makeCol(le, 1)) flag = true, ++ le ; while(ri >= le && !makeCol(ri, 2)) flag = true, -- ri ; while(dw <= up && !makeRow(dw, 1)) flag = true, ++ dw ; while(up >= dw && !makeRow(up, 2)) flag = true, -- up ; if(!flag) break ; } // cerr << le << ' ' << ri << ' ' << dw << ' ' << up << endl ; if(le > ri || dw > up) break ; if(le == ri) { if(!col[le].empty()) { if(sz(col[le]) == 1) upset(col[le].back().se, 3, 0) ; else { if(~maskCol[le] >> 0 & 1) upset(col[le].front().se, 1, 0) ; if(~maskCol[le] >> 1 & 1) upset(col[le].back().se, 2, 0) ; } } break ; } if(dw == up) { if(!row[up].empty()) { if(sz(row[up]) == 1) upset(row[up].front().se, 0, 3) ; else { if(~maskRow[up] >> 0 & 1) upset(row[up].front().se, 0, 1) ; if(~maskRow[up] >> 1 & 1) upset(row[up].back().se, 0, 2) ; } } break ; } vector<pii> pot = {mp(le, 1), mp(ri, 2)} ; for(pii cur : pot) { if(!col[cur.fi].empty()) { if(sz(col[cur.fi]) == 1) upset(col[cur.fi].back().se, 3, cur.se) ; else { if(~maskCol[cur.fi] >> 0 & 1) upset(col[cur.fi].front().se, 1, cur.se) ; if(~maskCol[cur.fi] >> 1 & 1) upset(col[cur.fi].back().se, 2, cur.se) ; } } } pot = {mp(dw, 1), mp(up, 2)} ; for(pii cur : pot) { if(!row[cur.fi].empty()) { if(sz(row[cur.fi]) == 1) upset(row[cur.fi].back().se, cur.se, 3) ; else { if(~maskRow[cur.fi] >> 0 & 1) upset(row[cur.fi].front().se, cur.se, 1) ; if(~maskRow[cur.fi] >> 1 & 1) upset(row[cur.fi].back().se, cur.se, 2) ; } } } } for(int i = 1; i <= n; i ++) cout << mark[i] ; } } void kittncool() { cin >> n ; for(int i = 1; i <= n; i ++) { cin >> a[i].fi >> a[i].se ; } return sub6::solve() ; } signed main() { ios_base::sync_with_stdio(0) ; cin.tie(0) ; cout.tie(0) ; if(fopen(taskname".inp", "r")) { freopen(taskname".inp", "r", stdin) ; freopen(taskname".out", "w", stdout) ; } int t = 1 ; //cin >> t ; while(t --) { kittncool() ; } }

Main.cpp: In function 'int main()':
Main.cpp:185:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  185 |         freopen(taskname".inp", "r", stdin) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:186:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  186 |         freopen(taskname".out", "w", stdout) ;
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~