Add DFS

DSA/dfs.cpp

@@ -0,0 +1,59 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+vector<vector<int>> buildGraph(int n, const vector<pair<int,int>>& edges, bool directed = false) {
+    vector<vector<int>> adj(n);
+    for (auto &e : edges) {
+        int u = e.first, v = e.second;
+        adj[u].push_back(v);
+        if (!directed) adj[v].push_back(u);
+    }
+    return adj;
+}
+
+void dfsUtil(int u, const vector<vector<int>> &adj, vector<int> &visited, vector<int> &parent) {
+    visited[u] = 1;
+    cout << u << " ";
+    for (int v : adj[u]) {
+        if (!visited[v]) {
+            parent[v] = u;
+            dfsUtil(v, adj, visited, parent);
+        }
+    }
+}
+
+void dfs(const vector<vector<int>> &adj) {
+    int n = adj.size();
+    vector<int> visited(n, 0), parent(n, -1);
+    int components = 0;
+
+    for (int i = 0; i < n; ++i) {
+        if (!visited[i]) {
+            components++;
+            cout << "Component " << components << ": ";
+            dfsUtil(i, adj, visited, parent);
+            cout << "\n";
+        }
+    }
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int n, m;
+    cin >> n >> m;
+    vector<pair<int,int>> edges;
+    for (int i = 0; i < m; ++i) {
+        int u, v;
+        cin >> u >> v;
+        // --u; --v; // uncomment if input is 1-indexed
+        edges.emplace_back(u, v);
+    }
+
+    vector<vector<int>> adj = buildGraph(n, edges, false);
+    cout << "DFS Traversal:\n";
+    dfs(adj);
+
+    return 0;
+}