@@ -0,0 +1,696 @@
+# Definition for a binary tree node.%0Aclass TreeNode(object):%0A    def __init__(self, x):%0A        self.val = x%0A        self.left = None%0A        self.right = None%0A%0A%0Aclass Solution(object):%0A    def isValidBST(self, root):%0A        %22%22%22%0A        :type root: TreeNode%0A        :rtype: bool%0A        %22%22%22%0A%0A        def in_order_traverse(root):%0A            if root is None:%0A                return%0A            in_order_traverse(root.left)%0A            in_order.append(root.val)%0A            in_order_traverse(root.right)%0A%0A        in_order = %5B%5D%0A        in_order_traverse(root)%0A        for i in range(1, len(in_order)):%0A            if in_order%5Bi%5D %3C= in_order%5Bi - 1%5D:%0A                return False%0A        return True%0A

Validate Binary Search Tree