783. 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/

解題

Runtime: 0 ms, faster than 100.00%

Memory Usage: 2.4 MB, less than 12.77%

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func minDiffInBST(root *TreeNode) int {
    arr := make([]int, 0)
    res := 100000
    
    var inorder func(*TreeNode)
    inorder = func(root *TreeNode) {
        if root == nil {
            return 
        }
        
        inorder(root.Left)
        
        if len(arr)!=0 && root.Val - arr[len(arr)-1] < res { 
            res = root.Val - arr[len(arr)-1] 
        }
        arr = append(arr, root.Val)
        
        inorder(root.Right)
    }
    
    inorder(root)
    
    return res
}