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:
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Input: root = [4,2,6,1,3]
Output:
1
Example 2:
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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/​
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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
}
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