783. Minimum Distance Between BST Nodes #
题目 #
Given the root of a Binary Search Tree (BST), return the minimum difference between the values of any two different nodes in the tree.
Note: This question is the same as 530: https://leetcode.com/problems/minimum-absolute-difference-in-bst/
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 <= 10^5
题目大意 #
给你一个二叉搜索树的根节点 root ，返回 树中任意两不同节点值之间的最小差值 。
解题思路 #
- 本题和第 530 题完全相同。解题思路见第 530 题。
代码 #
package leetcode
import (
"math"
"github.com/halfrost/leetcode-go/structures"
)
// TreeNode define
type TreeNode = structures.TreeNode
/**
* Definition for a binary tree node.
* type TreeNode struct {
* Val int
* Left *TreeNode
* Right *TreeNode
* }
*/
func minDiffInBST(root *TreeNode) int {
res, nodes := math.MaxInt16, -1
dfsBST(root, &res, &nodes)
return res
}
func dfsBST(root *TreeNode, res, pre *int) {
if root == nil {
return
}
dfsBST(root.Left, res, pre)
if *pre != -1 {
*res = min(*res, abs(root.Val-*pre))
}
*pre = root.Val
dfsBST(root.Right, res, pre)
}
func min(a, b int) int {
if a > b {
return b
}
return a
}
func abs(a int) int {
if a > 0 {
return a
}
return -a
}