# Definition for a binary tree node.

# class TreeNode(object):

# def __init__(self, x):

# self.val = x

# self.left = None

# self.right = None

class Solution(object):

def minDiffInBST\(self, root\):

    """

    :type root: TreeNode

    :rtype: int

    """

    lst=\[\]

    result=\[\]

    node=root

    if root == None:

        return

    while node or lst:

        while node:

            result+=\[node.val\]

            lst.append\(node\)

            node = node.left

        node = lst.pop\(\)

        node = node.right



    result.sort\(\)

    diff=\[\]

    for i in range\(0,len\(result\)-1\):

        diff+=\[result\[i+1\]-result\[i\]\]

    diff.sort\(\)

    return diff\[0\]

keypoint：知道怎么非递归遍历