leetcode783 -- Minimum Distances Between BST Nodes

# 小郑之家~

### 题目

Given a Binary Search Tree (BST) with the root node root, return the minimum difference between the values of any two different nodes in the tree.

Example :

Input: root = [4,2,6,1,3,null,null]
Output: 1
Explanation:
Note that root is a TreeNode object, not an array.

The given tree [4,2,6,1,3,null,null] is represented by the following diagram:

4
/   \
2      6
/ \
1   3

while the minimum difference in this tree is 1, it occurs between node 1 and node 2, also between node 3 and node 2.



### 解答

class Solution:
def minDiffInBST(self, root: TreeNode) -> int:

res = []
if not root:
return
self.inorder(root, res)

minimum = float('inf')
for i in range(len(res)-1):
minimum = min(res[i+1]-res[i], minimum)
return minimum

def inorder(self, root, res):
if not root:
return

self.inorder(root.left, res)
res.append(root.val)
self.inorder(root.right, res)