leetcode-163周赛-1261-在污染的二叉树中查找元素

class FindElements:

    def __init__(self, root: TreeNode):
        self.d = set()
        def f(r, x):
            if r:
                self.d.add(x)
　　　　　　　　　 r.val = x
                f(r.left, 2 * x + 1)
                f(r.right, 2 * x + 2)
        f(root, 0)

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