cycle.js

Graphs/cycle.js

@@ -0,0 +1,56 @@
+class Graph {
+    constructor(vertices) {
+      this.vertices = vertices;
+      this.adjList = new Array(vertices);
+      for (let i = 0; i < vertices; i++) {
+        this.adjList[i] = [];
+      }
+    }
+
+    addEdge(v, w) {
+      this.adjList[v].push(w);
+      this.adjList[w].push(v);//Creating Adjacency list.
+    }
+
+    isCyclic() {
+      const visited = new Array(this.vertices).fill(false);
+
+      for (let i = 0; i < this.vertices; i++) {
+        if (!visited[i]) {
+          if (this.isCyclicUtil(i, -1, visited)) {//Checking if graph contains a cycle.
+            return true;
+          }
+        }
+      }
+
+      return false;
+    }
+
+    isCyclicUtil(v, parent, visited) {
+      visited[v] = true;
+
+      for (const neighbor of this.adjList[v]) {
+        if (!visited[neighbor]) {
+          if (this.isCyclicUtil(neighbor, v, visited)) {
+            return true;
+          }
+        } else if (neighbor !== parent) {
+          return true;
+        }
+      }
+
+      return false;
+    }
+  }
+
+  /*const graph = new Graph(4);
+  graph.addEdge(0, 1);
+  graph.addEdge(1, 2);
+  graph.addEdge(2, 3);
+
+  if (graph.isCyclic()) {
+    console.log("The graph contains a cycle.");
+  } else {
+    console.log("The graph does not contain a cycle.");
+  }
+  **/