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799. Minimum Distance Between Bst Nodes

Tree Depth-First Search Breadth-First Search Binary Search Tree Binary Tree

Problem - Minimum Distance Between Bst Nodes

Easy

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

 

Example 1:

Input: root = [4,2,6,1,3]
Output: 1

Example 2:

Input: root = [1,0,48,null,null,12,49]
Output: 1

 

Constraints:

  • The number of nodes in the tree is in the range [2, 100].
  • 0 <= Node.val <= 105

 

Note: This question is the same as 530: https://leetcode.com/problems/minimum-absolute-difference-in-bst/

Solutions

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# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def minDiffInBST(self, root: Optional[TreeNode]) -> int:
        result = float('inf')
        last = float('inf')

        def dfs(root: Optional[TreeNode]):
            if root is None:
                return
            dfs(root.left)
            nonlocal result, last
            result = min(result, abs(root.val - last))
            last = root.val
            dfs(root.right)

        dfs(root)
        return result

Submission Stats:

  • Runtime: 0 ms (100.00%)
  • Memory: 17.8 MB (69.41%)