From e9505085f8cd822f96ecb8b04284740cbab55ee8 Mon Sep 17 00:00:00 2001
From: Atishay Jain <69712595+atishayzn@users.noreply.github.com>
Date: Thu, 7 Oct 2021 00:36:59 +0530
Subject: [PATCH] Detect cycle in a directed graph

---
 Detect-cycle-in-a-directed-graph.cpp | 29 ++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 Detect-cycle-in-a-directed-graph.cpp

diff --git a/Detect-cycle-in-a-directed-graph.cpp b/Detect-cycle-in-a-directed-graph.cpp
new file mode 100644
index 000000000..c448ba0ca
--- /dev/null
+++ b/Detect-cycle-in-a-directed-graph.cpp
@@ -0,0 +1,29 @@
+class Solution
+{   public:
+    bool dfsCycle(int i,vector<int>adj[],int vis[],int dfsVis[]){
+        vis[i]=1;
+        dfsVis[i]=1;
+        for(auto u :adj[i]){
+            if(!vis[u]){
+                if(dfsCycle(u,adj,vis,dfsVis))return true;
+            }
+            else if(dfsVis[u])return true;
+        }
+        dfsVis[i]=0;
+        return false;
+    }
+    public:
+	//Function to detect cycle in a directed graph.
+	bool isCyclic(int V, vector<int> adj[]) 
+	{   
+	    int vis[V];
+	    int dfsVis[V];
+	    memset(vis,0,sizeof(vis));
+	    memset(dfsVis,0,sizeof(dfsVis));
+	   	for(int i=0;i<V;i++){
+	   	    if(!vis[i])
+	   	    if(dfsCycle(i,adj,vis,dfsVis))return true;
+	   	}
+	   	return false;
+	}
+};