tree-notes/9IterativePreOrderTraversal.cpp at main · coder-writes/tree-notes · GitHub

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#include<bits/stdc++.h>
usingnamespacestd;
structTreeNode
{
int data;
structTreeNode* left;
structTreeNode* right;

TreeNode(int val)
 {
 data = val;
 left = NULL;
 right = NULL;
 }

};
vector<int> iterativePreOrderTraversalUsingStack(TreeNode* root){
 vector<int>ans;
if(root==NULL) return ans;
 stack<TreeNode*> st;
 st.push(root);
while(!st.empty()){
 TreeNode* node = st.top();
 st.pop();
if(node->right) st.push(node->right);
if(node->left) st.push(node->left);

 ans.push_back(node->data);
 }
}

intmain(){
structTreeNode* root = newTreeNode(2);
 root->left = newTreeNode(5);
 root->left->left = newTreeNode(4);
 root->left->left->left = newTreeNode(3);
 root->left->left->right = newTreeNode(2);
 root->left->right = newTreeNode(5);
 root->right = newTreeNode(7);
 root->right->left = newTreeNode(9);
 root->right->left->right = newTreeNode(2);
 root->right->left->right->right = newTreeNode(4);
 root->right->left->right->left = newTreeNode(1);
 root->right->left->left = newTreeNode(3);
 root->right->right = newTreeNode(7);

 vector<int> res = iterativePreOrderTraversalUsingStack(root);

for(auto val: res){
 cout<<val<<endl;
 }


}