Merge pull request Anuja-19#41 from SSKale1/main

Added BFS and DFS Graph Traversals

Cpp/bfs_dfs.cpp

@@ -0,0 +1,178 @@
+/*
+A C++ Program to implement BFS and DFS traversal of a Graph.
+The major difference between BFS and DFS is
+that BFS uses a queue for handling vertices, while DFS uses a stack.
+*/
+
+#include <bits/stdc++.h>
+//Macro to define the maximum vertices of the graph.
+#define MAX 100
+
+using namespace std;
+
+//Function for BFS Traversal. 
+void BFS(int source, int graph[][MAX], int n)
+{
+    queue<int> q;
+    int i, visited[MAX] = {0}, counter = 0;
+    q.push(source);
+    visited[source] = 1;
+
+    while (!q.empty())
+    {
+        counter++;
+        source = q.front();
+        q.pop();
+        cout << source;
+        if (counter < n)
+        {
+            cout << " --> ";
+        }
+
+        for (i = 0; i < n; i++)
+        {
+            if (graph[source][i] == 1 && visited[i] == 0)
+            {
+                q.push(i);
+                visited[i] = 1;
+            }
+        }
+    //Code fragment to traverse disconnected Graph
+        if (q.empty() && counter < n)
+        {
+            for (i = 0; i < n; i++)
+            {
+                if (visited[i] == 0)
+                {
+                    q.push(i);
+                    visited[i] = 1;
+                }
+            }
+        }
+    }
+}
+
+//Function for DFS Traversal
+void DFS(int source, int graph[][MAX], int n)
+{
+    stack<int> s;
+    int i, visited[MAX] = {0}, counter = 0;
+
+    visited[source] = 1;
+    s.push(source);
+    do
+    {
+        counter++;
+        source = s.top();
+        s.pop();
+        cout << source;
+        if (counter < n)
+        {
+            cout << " --> ";
+        }
+        for (i = 0; i < n; i++)
+        {
+            if (graph[source][i] == 1 && visited[i] == 0)
+            {
+                s.push(i);
+                visited[i] = 1;
+            }
+        }
+
+    //Code fragment to traverse disconnected Graph
+        if (s.empty() && counter < n)
+        {
+            for (i = 0; i < n; i++)
+            {
+                if (visited[i] == 0)
+                {
+                    s.push(i);
+                    visited[i] = 1;
+                }
+            }
+        }
+
+    } while (!s.empty());
+}
+
+int main()
+{
+    int graph[MAX][MAX];
+    int v1, v2, source, i, j, n, e;
+    cout << "Enter the number of Vertices and Edges of the Graph:\n";
+    cin >> n;
+    cin >> e;
+    for (i = 0; i < n; i++)
+    {
+        for (j = 0; j < n; j++)
+        {
+            graph[i][j] = 0;
+        }
+    }
+
+    cout << "\nEnter the " << e << " Edges of the Graph" << endl;
+
+    for (i = 0; i < e; i++)
+    {
+        cin >> v1;
+        cout << "\033[1A\033[1C --> ";
+        cin >> v2;
+        graph[v1][v2] = 1;
+        cout << "\n";
+    }
+
+    cout << "Enter the staring vertex\n";
+    cin >> source;
+
+    cout << "DFS Traversal for the matrix is " << endl;
+    DFS(source, graph, n);
+    cout << "\n\n";
+    cout << "BFS Traversal for the matrix is " << endl;
+    BFS(source, graph, n);
+
+    return 0;
+}
+
+/*
+Test I/O
+Enter the number of Vertices and Edges of the Graph:
+10
+14
+
+Enter the 14 Edges of the Graph
+0 --> 1
+
+0 --> 3
+
+3 --> 1
+
+1 --> 2
+
+2 --> 3
+
+0 --> 4
+
+4 --> 5
+
+5 --> 6
+
+6 --> 5
+
+4 --> 7
+
+7 --> 0
+
+9 --> 7
+
+9 --> 8
+
+8 --> 7
+
+Enter the staring vertex
+0
+DFS Traversal for the matrix is 
+0 --> 4 --> 7 --> 5 --> 6 --> 3 --> 1 --> 2 --> 9 --> 8
+
+BFS Traversal for the matrix is 
+0 --> 1 --> 3 --> 4 --> 2 --> 5 --> 7 --> 6 --> 8 --> 9
+*/