# Definition for a binary tree node.
# in order tree traverse can get a sorted list for BST
# The minimum value difference between two neighbors in a sorted list is the answer.
from utils import stringToTreeNode, prettyPrintTree
class Solution:
def getMinimumDifference(self, root):
L = []
def dfs(node):
if node.left: dfs(node.left)
L.append(node.val)
if node.right: dfs(node.right)
dfs(root)
return min(b - a for a, b in zip(L, L[1:]))
if __name__ == "__main__":
t = stringToTreeNode("[2, 1, 3]")
prettyPrintTree(t)
print(Solution().getMinimumDifference(t))
def printParseTreeFromFile(infile):
import utils
utils.prettyPrintTree(_parseFile(infile))
def printAstFromFile(infile):
import utils
utils.prettyPrintTree(_genAstFromFile(infile))
from typing import List
from utils import TreeNode, prettyPrintTree
class Solution:
def buildTree(self, preorder: List[int], inorder: List[int]) -> TreeNode:
if len(preorder) == 0:
return None
mid = inorder.index(preorder[0])
t = TreeNode(preorder[0])
t.left = self.buildTree(preorder[1:mid + 1], inorder[:mid])
t.right = self.buildTree(preorder[mid + 1:], inorder[mid + 1:])
return t
if __name__ == "__main__":
preorder = [3, 9, 20, 15, 7]
inorder = [9, 3, 15, 20, 7]
prettyPrintTree(Solution().buildTree(preorder, inorder))