数组中两个数的最大异或值

from typing import Listclass Solution:    def findMaximumXOR(self, nums: List[int]) -> int:        root = {}        for x in nums:            node = root            for b in range(31, -1, -1):                bit = (x >> b) & 1                node = node.setdefault(bit, {})        ans = 0        for x in nums:            node = root            cur = 0            for b in range(31, -1, -1):                bit = (x >> b) & 1                want = bit ^ 1                if want in node:                    cur |= 1 << b                    node = node[want]                else:                    node = node[bit]            ans = max(ans, cur)        return ans