How to implement a inorder traversal of a BST returning a li

How to implement a inorder traversal of a BST returning a list? Basically public List inorder() {}

Solution

In order traversal using list we can use stack .inorder check current node is empty

Traverse left subtree by recursively calling the function

Add to list

Traverse right subtree by calling recursively function and store in list.

public List<Integer> inorder(TreeNode root) {

List<Integer> list = new ArrayList<Integer>();

Stack<TreeNode> stack = new Stack<TreeNode>();

while(!stack.isEmpty() || root!=null){

if(root!=null){

stack.push(root);

root=root.left;

}else{

root = (TreeNode) stack.pop();

list.add(root.val);

root = root.right;

}

}

return list;

}