iterativebfs.cpp

graph/iterative_bfs.cpp

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+#include<bits/stdc++.h> 
+using namespace std; 
+
+// This class represents a directed graph using adjacency 
+// list representation 
+class Graph 
+{ 
+    int V;    // No. of vertices 
+    list<int> *adj;    // adjacency lists 
+public: 
+    Graph(int V);  // Constructor 
+    void addEdge(int v, int w); // to add an edge to graph 
+    void DFS(int s);  // prints all vertices in DFS manner 
+    // from a given source. 
+}; 
+
+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. 
+} 
+
+// prints all not yet visited vertices reachable from s 
+void Graph::DFS(int s) 
+{ 
+    // Initially mark all verices as not visited 
+    vector<bool> visited(V, false); 
+
+    // Create a stack for DFS 
+    stack<int> stack; 
+
+    // Push the current source node. 
+    stack.push(s); 
+
+    while (!stack.empty()) 
+    { 
+        // Pop a vertex from stack and print it 
+        s = stack.top(); 
+        stack.pop(); 
+
+        // Stack may contain same vertex twice. So 
+        // we need to print the popped item only 
+        // if it is not visited. 
+        if (!visited[s]) 
+        { 
+            cout << s << " "; 
+            visited[s] = true; 
+        } 
+
+        // Get all adjacent vertices of the popped vertex s 
+        // If a adjacent has not been visited, then puah it 
+        // to the stack. 
+        for (auto i = adj[s].begin(); i != adj[s].end(); ++i) 
+            if (!visited[*i]) 
+                stack.push(*i); 
+    } 
+} 
+
+// Driver program to test methods of graph class 
+int main() 
+{ 
+    Graph g(5); // Total 5 vertices in graph 
+    g.addEdge(1, 0); 
+    g.addEdge(0, 2); 
+    g.addEdge(2, 1); 
+    g.addEdge(0, 3); 
+    g.addEdge(1, 4); 
+
+    cout << "Following is Depth First Traversal\n"; 
+    g.DFS(0); 
+
+    return 0; 
+}