题目
Given a non-empty array of numbers, a0, a1, a2, … , an-1, where 0 ≤ ai < 231.
Find the maximum result of ai XOR aj, where 0 ≤ i, j < n.
Could you do this in O(n) runtime?
解题思路
从最高位开始，先假设该位置可以为1，然后与每个数进行异或，查看结果是否也在输入的数中，如果不在，则该位为0
代码
class Solution:
def findMaximumXOR(self, nums: List[int]) -> int:
res = 0
for i in range(31, -1, -1):
res <<= 1
pre = {n >> i for n in nums}
res += any(res ^ 1 ^ p in pre for p in pre)
return res
