class Trie:
    def __init__(self):
        self.val = None
        self.count = 0
        self.children = [None, None]

    def add(self, val, nbits):
        cur = self
        for cur_bit_idx in range(nbits - 1, -1, -1):
            cur_bit = 1 if (val & (1 << cur_bit_idx)) else 0
            if cur.children[cur_bit] is None:
                cur.children[cur_bit] = Trie()

            if cur_bit_idx == 0:
                cur.children[cur_bit].val = val

            cur.count += 1
            cur = cur.children[cur_bit]
        cur.count += 1

    def get_max(self, val, nbits):
        cur = self
        for cur_bit_idx in range(nbits - 1, -1, -1):
            cur_bit = 1 if (val & (1 << cur_bit_idx)) else 0
            non_cur_bit = 0 if cur_bit else 1

            bit_to_use = cur_bit
            if cur.children[non_cur_bit] and cur.children[non_cur_bit].count > 0:
                bit_to_use = non_cur_bit
            cur = cur.children[bit_to_use]
        return val ^ cur.val


    def repr(self):
        cs = []
        for c in self.children:
            if not c:
                cs.append(None)
            else:
                cs.append(c.repr())
        return (self.val, self.count, cs)


class Solution:
    def findMaximumXOR(self, nums: List[int]) -> int:
        N = len(nums)

        nums.sort()
        if nums[-1] == 0:
            return 0

        nbits = nums[-1].bit_length()

        ans = 0
        trie = Trie()
        for i, n in enumerate(nums):
            if i > 0:
                ans = max(ans, trie.get_max(n, nbits))
            trie.add(n, nbits)
        return ans