<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, word):
        curr = self.root
        for c in word:
            if curr.children[int(c)] == None:
                curr.children[int(c)] = TrieNode()
            curr = curr.children[int(c)]
            # if c not in curr.children:
            #     curr.children[c] = TrieNode()
            # curr = curr.children[c]

    def search(self, word):
        curr = self.root
        num = 0
        for c in word:
            if c == "0" and curr.children[1]:
                num = (num<<1) + 1
                curr = curr.children[1]
            elif c=="1" and curr.children[0]:
                num = (num <<1) + 1
                curr = curr.children[0]
            else:
                num = num << 1
                curr = curr.children[int(c)]
        return num

    def startsWith(self, prefix):
        curr = self.root
        for c in prefix:
            if c not in curr.children:
                return False
            curr = curr.children[c]
        return True

class Solution:
    def findMaximumXOR(self, nums: List[int]) -> int:
        root = Trie()
        result = 0
        max_len = len(bin(max(nums)))
        for j,num in enumerate(nums):
            arr = ["0"]*max_len
            for i in range(max_len):
                arr[max_len - i-1] = str((num>>i)&1)
            if j != 0:
                result = max(root.search(arr),result)
            root.insert(arr)
        return result
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