func_code_string: #include <bits/stdc++.h>   using namespace std;   const int IINF = 0x3f3f3f3f;   const long long LINF = 0x3f3f3f3f3f3f3f3fll;   const double DINF = numeric_limits<double>::infinity();   const int MOD = 1000000007;   const double EPS = 1e-9;   const double PI = acos(-1.0);   const int DX[] = {1, 0, -1, 0, 1, -1, 1, -1};   const int DY[] = {0, 1, 0, -1, 1, -1, -1, 1};   long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }   long long sqr(long long x) { return x * x; }   long long sqr(int x) { return (long long)x * x; }   double sqr(double x) { return x * x; }   long double sqr(long double x) { return x * x; }   mt19937 mmtw(960172);   long long rnd(long long x, long long y) {     static uniform_int_distribution<long long> d;     return d(mmtw) % (y - x + 1) + x;   }   const int N = 1011;   struct Line {     vector<int> cs;     int si0;   };   struct Seg {     int x, y1, y2;   };   int vc1, vc2;   Seg vs1[N], vs2[N];   vector<int> e[N];   int p2[N];   int p1[N];   bool vis1[N];   bool ok1[N], ok2[N];   bool dfs(int v) {     if (vis1[v]) return false;     vis1[v] = true;     for (int nv : e[v]) {       if (p2[nv] == -1) {         p2[nv] = v;         p1[v] = nv;         return true;       } else if (dfs(p2[nv])) {         p2[nv] = v;         p1[v] = nv;         return true;       }     }     return false;   }   void dfs2(int v) {     if (vis1[v]) return;     vis1[v] = 1;     for (int nv : e[v])       if (p2[nv] != -1) dfs2(p2[nv]);   }   int main() {     memset(p1, -1, sizeof(p1));     memset(p2, -1, sizeof(p2));     ios::sync_with_stdio(false);     int n;     scanf( %d , &n);     map<int, Line> mx, my;     for (int i = 0; i < n; ++i) {       int x, y;       scanf( %d%d , &x, &y);       mx[x].cs.push_back(y);       my[y].cs.push_back(x);     }     for (auto& p : mx) {       int x = p.first;       Line& l = p.second;       sort((l.cs).begin(), (l.cs).end());       l.si0 = vc1;       for (int i = 0; i < ((int)((l.cs).size())) - 1; ++i)         vs1[vc1++] = {x, l.cs[i], l.cs[i + 1]};     }     for (auto& p : my) {       int y = p.first;       Line& l = p.second;       sort((l.cs).begin(), (l.cs).end());       l.si0 = vc2;       for (int i = 0; i < ((int)((l.cs).size())) - 1; ++i)         vs2[vc2++] = {y, l.cs[i], l.cs[i + 1]};     }     for (int i = 0; i < vc1; ++i)       for (int j = 0; j < vc2; ++j) {         Seg s1 = vs1[i];         Seg s2 = vs2[j];         if (s1.y1 < s2.x && s2.x < s1.y2)           if (s2.y1 < s1.x && s1.x < s2.y2) {             e[i].push_back(j);           }       }     while (true) {       bool was = false;       memset(vis1, 0, sizeof(bool) * vc1);       for (int i = 0; i < vc1; ++i)         if (p1[i] == -1 && dfs(i)) was = true;       if (!was) break;     }     memset(vis1, 0, sizeof(bool) * vc1);     for (int i = 0; i < vc1; ++i)       if (p1[i] == -1) dfs2(i);     for (int i = 0; i < vc1; ++i)       if (vis1[i]) ok1[i] = 1;     for (int i = 0; i < vc2; ++i)       if (p2[i] == -1 || !vis1[p2[i]]) ok2[i] = 1;     struct Ans {       int x1, y1, x2, y2;     };     vector<Ans> ans;     for (auto const& p : my) {       int y = p.first;       Line const& l = p.second;       int i = 0;       while (i < ((int)((l.cs).size()))) {         int j = i;         while (j < ((int)((l.cs).size())) - 1) {           int id = l.si0 + j;           if (ok2[id])             ++j;           else             break;         }         ans.push_back({l.cs[i], y, l.cs[j], y});         i = j + 1;       }     }     cout << ((int)((ans).size())) <<   n ;     for (auto s : ans)       cout << s.x1 <<     << s.y1 <<     << s.x2 <<     << s.y2 <<   n ;     ans.clear();     for (auto const& p : mx) {       int x = p.first;       Line const& l = p.second;       int i = 0;       while (i < ((int)((l.cs).size()))) {         int j = i;         while (j < ((int)((l.cs).size())) - 1) {           int id = l.si0 + j;           if (ok1[id])             ++j;           else             break;         }         ans.push_back({x, l.cs[i], x, l.cs[j]});         i = j + 1;       }     }     cout << ((int)((ans).size())) <<   n ;     for (auto s : ans)       cout << s.x1 <<     << s.y1 <<     << s.x2 <<     << s.y2 <<   n ;     return 0;   }   