Add approach for finding articulation points

graph/articulationpnt.cpp

@@ -0,0 +1,44 @@
+#include<bits/stdc++.h>
+using namespace std;
+int timer=0;
+void dfs(int node,int par,vector<int> &in,vector<int> &low,vector<bool> &vis,vector<int> adj[]){
+    vis[node]=true;
+    in[node]=low[node]=timer;
+    timer++;
+    int children=0;
+    for(auto child:adj[node]){
+        if(child == par)
+            continue;
+        else if(vis[child]){
+            // the edge node-child is a back edge
+            low[node]=min(low[node],in[child]);
+        }
+        else{
+            dfs(child,node,in,low,vis,adj);
+            if(low[child] >= in[node] && par != -1){
+                // for 1 based numbering
+                cout<<node+1<<" is a Articulation Point\n";
+            }
+            low[node]=min(low[node],low[child]);
+            children++;
+        }
+    }
+    if(children > 1 && par == -1){
+        cout<<node+1<<" is a Articulation Point\n";
+    }
+}
+int main(){
+    int n,e;
+    cin>>n>>e;
+    vector<int> adj[n];
+    for(int i=0;i<e;i++){
+        int u,v;
+        cin>>u>>v;
+        adj[u-1].push_back(v-1);
+        adj[v-1].push_back(u-1);
+    }
+    vector<int> in(n),low(n);
+    vector<bool> vis(n,false);
+    dfs(0,-1,in,low,vis,adj);
+    return 0;
+}