Create KosarajuAlgo.cpp

Graphs/KosarajuAlgo.cpp

@@ -0,0 +1,64 @@
+class Solution
+{
+	private:
+
+	void dfs(int node, vector<int>&visited,vector<vector<int>>& adj,stack<int>&st){
+	    visited[node]=1;
+	    for(auto it:adj[node]){
+	        if(!visited[it]){
+	            dfs(it,visited,adj,st);
+	        }
+	    }
+	    st.push(node);
+	}
+	//Function to find number of strongly connected components in the graph.
+
+
+	void dfs3(int node,vector<int>&visited,vector<int> adjT[]){
+	      visited[node]=1;
+	    for(auto it:adjT[node]){
+	        if(!visited[it]){
+	            dfs3(it,visited,adjT);
+	        }
+	    }
+
+	}
+	public:
+    int kosaraju(int V, vector<vector<int>>& adj)
+    {
+        //code here
+        // Step-1 Sort all edges on the basis of finishing time
+        vector<int>visited(V,0);
+        stack<int>st;
+
+        for(int i=0;i<V;i++){
+            if(!visited[i]){
+                dfs(i,visited,adj,st);
+            }
+        }
+
+        // Step-2 Reverse the Graph
+        vector<int>adjT[V];
+        for(int i=0;i<V;i++){
+            visited[i]=0;
+            for(auto it:adj[i]){
+                // i->it;
+                adjT[it].push_back(i);
+            }
+        }
+        // Step-3 Do DFS
+        int scc=0;
+        while(!st.empty()){
+            int node=st.top();
+            st.pop();
+
+
+            if(!visited[node]){
+                scc++;
+                dfs3(node,visited,adjT);
+            }
+        }
+
+        return scc;
+    }
+};