<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 TrieNode:
    def __init__(self):
        self.children = [None, None]

class Trie:
    def __init__(self):
        self.root = TrieNode()
    
    def insert(self, s):
        node = self.root
        for c in s:
            x = int(c)
            if node.children[x] is None:
                node.children[x] = TrieNode()
            node = node.children[x]

    def get_max(self, s):
        ret = 0
        node = self.root
        for c in s:
            x = int(c)
            ret <<= 1
            if node.children[1 - x] is not None:
                node = node.children[1 - x]
                ret += 1
            else:
                node = node.children[x]
            
        return ret

class Solution:
    def findMaximumXOR(self, nums: List[int]) -> int:
        max_num = max(nums)
        trie = Trie()
        
        nums = [bin(num)[2:].zfill(32) for num in nums]
        for num in nums:
            trie.insert(num)
        
        ans = 0
        for num in nums:
            ans = max(ans, trie.get_max(num))
            print (num, ans)
        return ans

# 3  0 0011
# 2  0 0010
# 5  0 0101
# 10 0 1010
# 8  0 1000

# 25 1 1001
#    1 0101
518690