Create Vertex Cover Problem

Author: abrar-syed

Vertex Cover Problem

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+// Program to print Vertex Cover of a given undirected graph 
+#include<iostream> 
+#include <list> 
+using namespace std; 
+
+// This class represents a undirected graph using adjacency list 
+class Graph 
+{ 
+	int V; // No. of vertices 
+	list<int> *adj; // Pointer to an array containing adjacency lists 
+public: 
+	Graph(int V); // Constructor 
+	void addEdge(int v, int w); // function to add an edge to graph 
+	void printVertexCover(); // prints vertex cover 
+}; 
+
+Graph::Graph(int V) 
+{ 
+	this->V = V; 
+	adj = new list<int>[V]; 
+} 
+
+void Graph::addEdge(int v, int w) 
+{ 
+	adj[v].push_back(w); // Add w to v’s list. 
+	adj[w].push_back(v); // Since the graph is undirected 
+} 
+
+// The function to print vertex cover 
+void Graph::printVertexCover() 
+{ 
+	// Initialize all vertices as not visited. 
+	bool visited[V]; 
+	for (int i=0; i<V; i++) 
+		visited[i] = false; 
+
+	list<int>::iterator i; 
+
+	// Consider all edges one by one 
+	for (int u=0; u<V; u++) 
+	{ 
+		// An edge is only picked when both visited[u] and visited[v] 
+		// are false 
+		if (visited[u] == false) 
+		{ 
+			// Go through all adjacents of u and pick the first not 
+			// yet visited vertex (We are basically picking an edge 
+			// (u, v) from remaining edges. 
+			for (i= adj[u].begin(); i != adj[u].end(); ++i) 
+			{ 
+				int v = *i; 
+				if (visited[v] == false) 
+				{ 
+					// Add the vertices (u, v) to the result set. 
+					// We make the vertex u and v visited so that 
+					// all edges from/to them would be ignored 
+					visited[v] = true; 
+					visited[u] = true; 
+					break; 
+				} 
+			} 
+		} 
+	} 
+
+	// Print the vertex cover 
+	for (int i=0; i<V; i++) 
+		if (visited[i]) 
+		cout << i << " "; 
+} 
+
+// Driver program to test methods of graph class 
+int main() 
+{ 
+	// Create a graph given in the above diagram 
+	Graph g(7); 
+	g.addEdge(0, 1); 
+	g.addEdge(0, 2); 
+	g.addEdge(1, 3); 
+	g.addEdge(3, 4); 
+	g.addEdge(4, 5); 
+	g.addEdge(5, 6); 
+
+	g.printVertexCover(); 
+
+	return 0; 
+}