Add articulation points

Author: coderick14

articultion_points.cpp

@@ -0,0 +1,63 @@
+#include <bits/stdc++.h>
+#define ll long long
+#define INF 1e18
+using namespace std;
+
+vector<vector<ll>> adj;
+vector<ll> low, discover;
+vector<bool> visited;
+set<ll> articulation_pts;
+ll timer = 0;
+
+
+void explore(ll u, ll p = 0) {
+	visited[u] = true;
+	discover[u] = low[u] = ++timer;
+
+	ll children = 0;
+	for (ll v : adj[u]) {
+		if (visited[v] == false) {
+			children++;
+			explore(v,u);
+			low[u] = min(low[u], low[v]);
+			if (p == 0 and children > 1) {
+				articulation_pts.insert(u);
+			}
+			if (p != 0 and low[v] >= discover[u]) {
+				articulation_pts.insert(u);
+			}
+		}
+		else if (v != p) {
+			low[u] = min(low[u], discover[v]);
+		}
+	}
+}
+
+void dfs(ll n) {
+	ll i;
+	for (i = 1; i <= n; i++) {
+		if (visited[i] == false) {
+			explore(i);
+		}
+	}
+}
+
+int main() {
+	ll n, m, i, u, v;
+	cin >> n >> m;
+	adj.resize(n+1);
+	discover.resize(n+1);
+	low.resize(n+1);
+	visited.assign(n+1,false);
+
+	for (i = 0; i < m; i++) {
+		cin >> u >> v;
+		adj[u].push_back(v);
+		adj[v].push_back(u);
+	}
+	dfs(n);
+	for (ll pt : articulation_pts) {
+		cout << pt << endl;
+	}
+	return 0;
+}