We use cookies to ensure you have the best browsing experience on our website. Please read our cookie policy for more information about how we use cookies.
  1. Trees: Is This a Binary Search Tree?
  2. Discussions

Trees: Is This a Binary Search Tree?

  • Dan_Golding
     + 1 comment

    I ended up with pretty much the same code but instead of a closure variable I just passed the variable in. I used a single element list since it's gets passed by reference which allows changes to persist when going back down the call stack:

    def checkBST(root):
    return(check_in_order(root,[-1]))
    
def check_in_order(root,prev):
    result = True
    if root.left is not None:
        result &= check_in_order(root.left,prev)
    if prev[0] >= root.data:
        return False
    prev[0] = root.data
    if root.right is not None:
        result &= check_in_order(root.right,prev)
    return result