#include <bits/stdc++.h> using namespace std; #define int long long struct Edge { int v; int id; }; void dfs1(int u, vector<int> &vis, vector<int> &par_edge, const vector<vector<Edge>> &g) { vis[u] = 1; for (const Edge &e : g[u]) { int vv = e.v; if (e.id == par_edge[u]) continue; // skip parent edge if (!vis[vv]) { par_edge[vv] = e.id; dfs1(vv, vis, par_edge, g); } } } void dfs2(int u, vector<int> &vis, vector<int> &par_edge, vector<int> &used, vector<int> &deg, const vector<vector<Edge>> &g) { vis[u] = 1; for (const Edge &e : g[u]) { int v = e.v; if (vis[v] || par_edge[v] != e.id) continue; // only traverse child-side tree edges dfs2(v, vis, par_edge, used, deg, g); if (!used[e.id] && deg[u] < 2 && deg[v] < 2) { used[e.id] = 1; deg[u]++; deg[v]++; } } } signed main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n; if (!(cin >> n)) return 0; vector<int> x(n), y(n); for (int i = 0; i < n; ++i) cin >> x[i] >> y[i]; // coordinate compression vector<int> xs = x, ys = y; sort(xs.begin(), xs.end()); xs.erase(unique(xs.begin(), xs.end()), xs.end()); sort(ys.begin(), ys.end()); ys.erase(unique(ys.begin(), ys.end()), ys.end()); int nx = (int)xs.size(); int ny = (int)ys.size(); int V = nx + ny; vector<int> cx(n), cy(n); for (int i = 0; i < n; ++i) { cx[i] = int(lower_bound(xs.begin(), xs.end(), x[i]) - xs.begin()); cy[i] = int(lower_bound(ys.begin(), ys.end(), y[i]) - ys.begin()) + nx; } // adjacency sized to actual number of vertices vector<vector<Edge>> g(V); for (int i = 0; i < n; ++i) { g[cx[i]].push_back({cy[i], i}); g[cy[i]].push_back({cx[i], i}); } // arrays sized to V or n (not hard-coded large constants) vector<int> vis(V, 0); vector<int> par_edge(V, -1); vector<int> deg(V, 0); vector<int> used(n, 0); // DFS #1: build spanning forest and fill par_edge (edge id for child) for (int i = 0; i < V; ++i) { if (!vis[i]) dfs1(i, vis, par_edge, g); } // Select cycle (non-tree) edges if they don't violate deg <= 2 for (int i = 0; i < n; ++i) { int u = cx[i], v = cy[i]; // If the edge i is not the tree edge of either endpoint, it's a non-tree (cycle) edge if (par_edge[u] != i && par_edge[v] != i) { if (deg[u] < 2 && deg[v] < 2) { used[i] = 1; deg[u]++; deg[v]++; } } } // DFS #2 (postorder): process tree edges fill(vis.begin(), vis.end(), 0); for (int i = 0; i < V; ++i) { if (!vis[i]) dfs2(i, vis, par_edge, used, deg, g); } // Output for (int i = 0; i < n; ++i) cout << used[i]; cout << '\n'; return 0; }

Main.cpp: In function 'int main()':
Main.cpp:4:13: error: expected primary-expression before 'long'
    4 | #define int long long
      |             ^~~~
Main.cpp:59:17: note: in expansion of macro 'int'
   59 |         cx[i] = int(lower_bound(xs.begin(), xs.end(), x[i]) - xs.begin());
      |                 ^~~
Main.cpp:4:13: error: expected primary-expression before 'long'
    4 | #define int long long
      |             ^~~~
Main.cpp:60:17: note: in expansion of macro 'int'
   60 |         cy[i] = int(lower_bound(ys.begin(), ys.end(), y[i]) - ys.begin()) + nx;
      |                 ^~~