BuildBST.java

public class BuildBST {
    
    public static class Node {
        int data;
        Node left;
        Node right;
        public Node(int data){
            this.data = data;
            this.left = this.right = null;
        }
    }

    public static Node buildBST(Node root, int val){
        if(root == null){
            root = new Node(val);
            return root;
        }

        if(root.data > val){
            root.left = buildBST(root.left, val);
        } else {
            root.right = buildBST(root.right, val);
        }

        return root;
    }

    public static void inorderTraversal(Node root){
        if(root == null){
            return;
        }
        inorderTraversal(root.left);
        System.out.print(root.data+" ");
        inorderTraversal(root.right);
    }

    public static void main(String[] args) {
        int arr[] = {5,1,3,4,2,7};
        Node root = null;
        for(int i=0; i<arr.length; i++){
          root = buildBST(root, arr[i]);
        }

        inorderTraversal(root);
    }
}