<p>Given an integer array <code>nums</code>, return <em>the maximum result of </em><code>nums[i] XOR nums[j]</code>, where <code>0 &lt;= i &lt;= j &lt; n</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [3,10,5,25,2,8]
<strong>Output:</strong> 28
<strong>Explanation:</strong> The maximum result is 5 XOR 25 = 28.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [14,70,53,83,49,91,36,80,92,51,66,70]
<strong>Output:</strong> 127
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= nums.length &lt;= 2 * 10<sup>5</sup></code></li>
	<li><code>0 &lt;= nums[i] &lt;= 2<sup>31</sup> - 1</code></li>
</ul>

class Solution:
    @staticmethod
    def rev(num):
        res = ""
        for char in num:
            if char == "0":
                res += "1"
            else:
                res += "0"
        return res

    @staticmethod
    def get_binary(num, N):
        res = ""
        while num > 0:
            modular = num % 2
            if modular == 1:
                res = "1" + res
            else:
                res = "0" + res
            num = num // 2
        res = "0" * (N - len(res)) + res
        return res

    def findMaximumXOR(self, nums: List[int]) -> int:
        # 1 0 1
        # 1 0 0 1 1
        # 0 0 1 1 1
        N = 31
        prefix_set = set()
        for num in nums:
            binary = Solution.get_binary(num, N)
            for i in range(N):
                prefix = binary[:i + 1]
                prefix_set.add(prefix)
        
        res = 0
        for num in nums:
            max_xor = 0
            target_binary = Solution.rev(Solution.get_binary(num, N))
            for i in range(N):
                if target_binary[:i+1] in prefix_set:
                    max_xor += 2**(N-1-i)
                else:
                    if target_binary[i] == "1":
                        target_binary = target_binary[:i] + "0" + target_binary[i+1:]
                    else:
                        target_binary = target_binary[:i] + "1" + target_binary[i+1:]
            res = max(res, max_xor)
        return res
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