Added BFS_traversal.cpp

Graph Theory/BFS/BFS_traversal.cpp

@@ -0,0 +1,65 @@
+//Code for BFS traversal of graph
+#include<bits/stdc++.h>
+using namespace std;
+
+
+
+/* Function to do BFS of graph
+*  adj[]: array of vectors
+*  vis[]: array to keep track of visited nodes
+*/
+void bfs(int s, vector<int> adj[], bool vis[], int N)
+{
+    queue<int> q;
+    q.push(s);
+    vis[s]=true;
+
+    while(!q.empty())
+    {
+        int u = q.front();
+        cout<<u<<" ";
+        q.pop();
+
+        for(auto v:adj[u])
+        {
+
+            if(!vis[v])
+            {
+                q.push(v);
+                vis[v] = true;   
+            }
+        }
+
+    }
+}
+
+
+//Driver Code Starts here.
+int main()
+{
+    int T;
+    cin>>T;
+    while(T--)
+    {
+        //N is number of nodes
+        //E is number of edges
+        int N, E;
+        cin>>N>>E;
+        vector<int> adj[N];
+        bool vis[N] = {false};  //initialize all values of vis array to false
+        for(int i=0;i<E;i++)
+        {
+            int u,v;
+            cin>>u>>v;
+            adj[u].push_back(v);
+
+            // for undirected graph add this line 
+            // adj[v].push_back(u);
+        }
+
+        bfs(0, adj, vis, N);
+
+        cout<<endl;
+
+    }
+}