272. Closest Binary Search Tree Value II (Hard) - TengnanYao/daily_leetcode GitHub Wiki

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:
    def closestKValues(self, root: Optional[TreeNode], target: float, k: int) -> List[int]:
        def dfs(root):
            if root:
                dfs(root.left)
                if len(self.result) < k:
                    self.result.append(root.val)
                    dfs(root.right)
                else:
                    if abs(root.val - target) < abs(self.result[0] - target):
                        self.result.append(root.val)
                        self.result.pop(0)
                        dfs(root.right)
        self.result = []
        dfs(root)
        return self.result