DFS and BFS Graph Traversal in C++

dfs_bfs.cpp

#include <iostream>
#include <unordered_map>
#include <vector>
#include <queue>
#include <stack>
#include <unordered_set>

class Graph {
private:
  std::unordered_map<int, std::vector<int>> adjList;

public:
    void addEdge(int u, int v) {
        adjList[u].push_back(v);
        adjList[v].push_back(u);
    }
    
    // Depth first search
    void dfs(int start) {
        std::unordered_set<int> visited; //track visited unordered_set
        std::stack<int> stack;
        
        stack.push(start);
        
        while (!stack.empty()) {
            int node = stack.top();
            stack.pop();
            
            if (visited.find(node) == visited.end()) {
                visited.insert(node);
                std::cout << "Visited: " << node << "\n";
                
                for (int neighbor : adjList[node]) {
                    if (visited.find(neighbor) == visited.end()) {
                        stack.push(neighbor);
                    }
                }
            }
        }
    }
    
    // BFS
    void bfs(int start) {
        std::unordered_set<int> visited;
        std::queue<int> queue;
        
        queue.push(start);
        visited.insert(start);
        
        while (!queue.empty()) {
            int node = queue.front();
            queue.pop();
            std::cout << "Visited: " << node << "\n";
            
            for (int neighbor : adjList[node]) {
                if (visited.find(neighbor) == visited.end()) {
                    visited.insert(neighbor);
                    queue.push(neighbor);
                }
            }
            
        }
        
    }
    
};

int main() {
    Graph g;

    // Add edges
    g.addEdge(1, 2);
    g.addEdge(1, 3);
    g.addEdge(2, 4);
    g.addEdge(3, 4);
    g.addEdge(4, 5);

    std::cout << "DFS Traversal:\n";
    g.dfs(1); // Start DFS from node 1

    std::cout << "\nBFS Traversal:\n";
    g.bfs(1); // Start BFS from node 1

    return 0;
}