BST

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

def checkBST(root):
    max = 10000
    min = 0
    data = {root.data}

    def checkBounds(data, leftBound, rightBound):
        #Case 1 - Not a BST
        return False if data < leftBound or data > rightBound else True


    def evaluateNode(node, lowerBound, upperBound):

        #Case 2 - Not a unique BST
        if node.data in data:
            return False
        else:
            data.add(node.data)

        if not checkBounds(node.data, lowerBound, upperBound): return False

        if node.left is not None:
            if not evaluateNode(node.left, lowerBound, node.data): return False

        if node.right is not None:
            if not evaluateNode(node.right, node.data, upperBound): return False

        return True

    #Left Side
    if not evaluateNode(root.left, min, root.data): return False


    #Right Side
    if not evaluateNode(root.right, root.data, max): return False

    return True