Minimum Absolute Difference in BST
Given the root of a Binary Search Tree (BST), return the minimum absolute difference between the values of any two different nodes.
Important BST Property
An inorder traversal of a BST gives values in sorted order:
Left → Root → Right
Therefore, the minimum difference will always be between two adjacent values in the inorder traversal.
Example
4
/ \
2 6
/ \
1 3
Inorder traversal:
1 2 3 4 6
Differences:
2 - 1 = 1 3 - 2 = 1 4 - 3 = 1 6 - 4 = 2
Answer:
1
Example 1
Input
root = [4,2,6,1,3]
Output
1
Explanation
The BST is:
4
/ \
2 6
/ \
1 3
Inorder traversal produces the sorted sequence:
1 2 3 4 6
Now compare adjacent values:
2 - 1 = 1 3 - 2 = 1 4 - 3 = 1 6 - 4 = 2
The minimum absolute difference is:
1
Example 2
Input
root = [1,0,48,null,null,12,49]
Output
1
Explanation
Inorder traversal gives:
0 1 12 48 49
Adjacent differences are:
1 - 0 = 1 12 - 1 = 11 48 - 12 = 36 49 - 48 = 1
Therefore, the minimum difference is:
1
Constraints
Hints:
Hint 1
Remember that inorder traversal of a BST produces values in sorted order.
Hint 2
You only need to compare adjacent values in the sorted sequence.
Author & Technical Reviewer
Technically reviewed by: ExamAdda Technical Review Team
Technical Reviewers, ExamAdda
Software engineers at ExamAdda who check every article's definitions, complexity claims and code examples before and after publishing.
Published
Aug 13, 2026
Last updated
Aug 14, 2026
Content Verification Methodology
Definitions and complexity claims were checked against authoritative computer-science references. Code examples were compiled and tested with standard, boundary and edge-case inputs.
Expected Output