Updated Binary Tree Section in Love Babbar DSA sheet

Love Babbar DSA Sheet/6. Binary Trees/1. Level order traversal/code.cpp

@@ -0,0 +1,97 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+/*Ques - Given a binary tree, find its level order traversal.
+
+Input - 1 3 2 -1 -1 -1 -1  
+
+Output - 1 3 2
+*/
+
+template <typename T> class Node{
+public:
+  T data;
+  Node* left;
+  Node* right;
+
+  Node(T data){
+    this -> data = data;
+    left = right = NULL;
+  }
+
+  ~Node(){
+    delete left;
+    delete right;
+  }
+};
+
+Node<int>* buildBinaryTree(){
+  int rootData;
+  cout << "Enter root data - ";
+  cin >> rootData;
+
+  Node<int>* root = new Node<int>(rootData);
+
+  queue<Node<int>*> pendingNodes;
+  pendingNodes.push(root);
+
+  while(!pendingNodes.empty()){
+    Node<int>* front = pendingNodes.front();
+    pendingNodes.pop();
+
+    int leftData;
+    cout << "Enter Left Child of " << front -> data << "\n";
+    cin >> leftData;
+
+    if(leftData != -1){
+      Node<int>* leftChild = new Node<int>(leftData);
+      front -> left = leftChild;
+      pendingNodes.push(leftChild);
+    }
+
+    int rightData;
+    cout << "Enter Right Child of " << front -> data << "\n";
+    cin >> rightData;
+
+    if(rightData != -1){
+      Node<int>* rightChild = new Node<int>(rightData);
+      front -> right = rightChild;
+      pendingNodes.push(rightChild);
+    }
+  }
+
+  return root;
+}
+
+void solution(Node<int>* root){
+  queue<Node<int>*> pendingNodes;
+  pendingNodes.push(root);
+
+  cout << root -> data << " "; 
+
+  while(!pendingNodes.empty()){
+    Node<int>* front = pendingNodes.front();
+    pendingNodes.pop();
+
+    if(front -> left){
+      cout << front -> left -> data << " ";
+      pendingNodes.push(front -> left);
+    }
+
+    if(front -> right){
+      cout << front -> right -> data << " ";
+      pendingNodes.push(front -> right);
+    }
+  }
+  cout << "\n";
+}
+
+int main(){
+
+  Node<int>* root = buildBinaryTree();
+
+  solution(root);
+
+  delete root;
+  return 0;
+}