Merge pull request #353 from Hardvan/graph_search_cpp

Add `GraphSearch.cpp`

Author: kelvins

README.md

@@ -246,8 +246,8 @@ In order to achieve greater coverage and encourage more people to contribute to
                 </a>
             </td>
             <td> <!-- C++ -->
-                <a href="./CONTRIBUTING.md">
-                    <img align="center" height="25" src="./logos/github.svg" />
+                <a href="./src/cpp/GraphSearch.cpp">
+                    <img align="center" height="25" src="./logos/cplusplus.svg" />
                 </a>
             </td>
             <td> <!-- Java -->

src/cpp/GraphSearch.cpp

@@ -0,0 +1,135 @@
+#include <iostream>
+#include <vector>
+#include <queue>
+
+#define MAX_VERTICES 6 // Maximum number of vertices in the graph
+
+// Structure that defines each Vertex of the Graph
+struct Vertex
+{
+    char id;
+    std::vector<Vertex *> neighbors; // List of neighbors
+    bool visited;
+
+    Vertex(char id) : id(id), visited(false) {}
+};
+
+// Creates a vertex and returns it
+Vertex *createVertex(char id)
+{
+    return new Vertex(id);
+}
+
+// Links two vertices (makes them neighbors)
+void linkVertices(Vertex *v1, Vertex *v2)
+{
+    v1->neighbors.push_back(v2); // Add v2 as a neighbor of v1
+    v2->neighbors.push_back(v1); // Add v1 as a neighbor of v2
+}
+
+/*
+ * Depth First Search (DFS)
+ * Recursively visits neighbors of the starting vertex
+ */
+int depthFirstSearch(Vertex *start, Vertex *destination, int steps)
+{
+    start->visited = true; // Mark the current vertex as visited
+    if (start == destination)
+        return steps; // If found, return the distance
+
+    for (Vertex *neighbor : start->neighbors)
+    { // Visit all neighbors
+        if (!neighbor->visited)
+        { // If neighbor hasn't been visited
+            int result = depthFirstSearch(neighbor, destination, steps + 1);
+            if (result != -1)
+                return result; // If destination found, return result
+        }
+    }
+    return -1; // Destination not found
+}
+
+/*
+ * Breadth First Search (BFS)
+ * Uses a queue to traverse level by level
+ */
+int breadthFirstSearch(Vertex *start, Vertex *destination)
+{
+    std::queue<Vertex *> q;
+    q.push(start); // Enqueue starting vertex
+    start->visited = true;
+
+    int steps = 0;
+
+    while (!q.empty())
+    {
+        int qSize = q.size(); // Current queue size (level size)
+
+        // Process all vertices at the current level
+        for (int i = 0; i < qSize; i++)
+        {
+            Vertex *current = q.front();
+            q.pop();
+
+            if (current == destination)
+                return steps; // If destination found, return steps
+
+            // Enqueue all unvisited neighbors
+            for (Vertex *neighbor : current->neighbors)
+            {
+                if (!neighbor->visited)
+                {
+                    neighbor->visited = true;
+                    q.push(neighbor);
+                }
+            }
+        }
+        steps++; // Increment the level
+    }
+    return -1; // Destination not found
+}
+
+int main()
+{
+    // Create vertices
+    Vertex *A = createVertex('A');
+    Vertex *B = createVertex('B');
+    Vertex *C = createVertex('C');
+    Vertex *D = createVertex('D');
+    Vertex *E = createVertex('E');
+    Vertex *F = createVertex('F');
+
+    // Link vertices as per the graph structure
+    linkVertices(A, B);
+    linkVertices(A, C);
+    linkVertices(B, D);
+    linkVertices(C, D);
+    linkVertices(B, E);
+    linkVertices(D, E);
+    linkVertices(E, F);
+    linkVertices(D, F);
+
+    // Perform Depth First Search
+    int result = depthFirstSearch(A, F, 0);
+    if (result != -1)
+        std::cout << "DFS - Found. Distance: " << result << std::endl;
+    else
+        std::cout << "DFS - Not Found." << std::endl;
+
+    // Reset visited status for all vertices
+    A->visited = false;
+    B->visited = false;
+    C->visited = false;
+    D->visited = false;
+    E->visited = false;
+    F->visited = false;
+
+    // Perform Breadth First Search
+    result = breadthFirstSearch(A, F);
+    if (result != -1)
+        std::cout << "BFS - Found. Distance: " << result << std::endl;
+    else
+        std::cout << "BFS - Not Found." << std::endl;
+
+    return 0;
+}