Preorder Traversal without recursion
Preorder Traversal without recursion vector <int> preorder(Node* root) { vector<int>v; stack<Node*>st; if(root==NULL) return v; st.push(root); while(!st.empty()) { Node * temp; temp=st.top(); st.pop(); v.push_back(temp->data); if(temp->right) st.push(temp->right); if(temp->left) ...