530. 二叉搜索树的最小绝对差

530. 二叉搜索树的最小绝对差

中序遍历递归实现

var pre *TreeNode
var res int
func dfs(root *TreeNode){
    if root==nil{
        return
    }
    dfs(root.Left)
    if pre!=nil {
        res = int(math.Min(math.Abs(float64(root.Val-pre.Val)),float64(res)))
    }
    pre = root
    dfs(root.Right)
}
func getMinimumDifference(root *TreeNode) int {
    res = math.MaxInt32
    dfs(root)
    return res
}
func main() {
    root :=&TreeNode{Val:   1}
    two :=&TreeNode{Val:   2}
    three :=&TreeNode{Val:   3}
    root.Right = three
    three.Left = two
    fmt.Println(getMinimumDifference(root))
}