golang 解法, 执行用时: 4 ms, 内存消耗: 6.5 MB, 提交时间: 2021-06-08 22:45:21

/**
 * Definition for singly-linked list.
 * type ListNode struct {
 *     Val int
 *     Next *ListNode
 * }
 */
/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func sortedListToBST(head *ListNode) *TreeNode {
    var nums []int
    for head != nil {
        nums = append(nums, head.Val)
        head = head.Next
    }
    return helper(nums, 0, len(nums)-1)
}

func helper(nums []int, left, right int) *TreeNode {
    if left > right {
        return nil
    }
    mid := ( left + right ) / 2
    root := &TreeNode{
        Val:nums[mid],
    }
    root.Left = helper(nums, left, mid-1)
    root.Right = helper(nums, mid+1, right)
    return root
}