【二叉树-中等】1261. 在受污染的二叉树中查找元素

【题目】

【代码】

# 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 FindElements:
    def __init__(self, root: Optional[TreeNode]):
        self.root=root
        self.num=[]
        def dfs(root,parent=-1):
            if not root:
                return
            if parent==-1:
                root.val=0
            self.num.append(root.val)
            if root and root.left:
                root.left.val=root.val*2+1
            if root and root.right:
                root.right.val=root.val*2+2
            dfs(root.left,root.val)
            dfs(root.right,root.val)
        dfs(root)

    def find(self, target: int) -> bool:
        return target in self.num