//golang递归

func inorderTraversal( root *TreeNode ) []int {
    // write code here
    res:=make([]int,0)
    midOrder(&res,root)
    return res
}

func midOrder(res *[]int,root *TreeNode){
    if root==nil{
        return
    }
    midOrder(res,root.Left)
    *res=append(*res, root.Val)
    midOrder(res,root.Right)
}