binarytreeattempt1

""" Node is defined as
class node:
    def __init__(self, data):
        self.data = data
        self.left = None
        self.right = None
"""

def check_binary_search_tree_(root, values = None):
    #print root.data
    #print root.left
    #print root.right

    toReturn = True

    if values == None:
        values = dict()

    if not root.data in values:
        values[root.data] = True
    else:
        return False

    if (root.left):
        if (root.left.data > root.data):
            return False
        else:
            toReturn = check_binary_search_tree_(root.left)

    if (root.right):
        if (root.right.data < root.data):
            return False
        else:
            toReturn = check_binary_search_tree_(root.right)
    return toReturn