Return the root node of a binary search tree that matches the given preorder traversal.
(Recall that a binary search tree is a binary tree where for every node, any descendant of node.left has a value < node.val, and any descendant of node.right has a value > node.val. Also recall that a preorder traversal displays the value of the node first, then traverses node.left, then traverses node.right.)
Example 1:
Input: [8,5,1,7,10,12]
Output: [8,5,10,1,7,null,12]
(Recall that a binary search tree is a binary tree where for every node, any descendant of node.left has a value < node.val, and any descendant of node.right has a value > node.val. Also recall that a preorder traversal displays the value of the node first, then traverses node.left, then traverses node.right.)
Example 1:
Input: [8,5,1,7,10,12]
Output: [8,5,10,1,7,null,12]
class Solution {
TreeNode root;
public TreeNode bstFromPreorder(int[] preorder) {
for(int i:preorder){
root = insert(root,i);
}
return root;
}
static TreeNode insert(TreeNode root, int data){
if(root == null){
root = new TreeNode(data);
return root;
}
if(data<root.val){
root.left = insert(root.left, data);
}else{
root.right = insert(root.right, data);
}
return root;
}
}