题目
Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target.
Note:
- Given target value is a floating point.
- You are guaranteed to have only one unique value in the BST that is closest to the target.
解题思路
从根开始和目标值进行比较，如果目标值小于当前节点，向左遍历，否则向右遍历
代码
class Solution:
def closestValue(self, root: TreeNode, target: float) -> int:
res = root.val
while root:
res = min(res, root.val, key = lambda x: abs(target - x))
root = root.left if target < root.val else root.right
return res
