<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 Node {
    vector<Node*> link;
public:
    Node() {
        link = vector<Node*>(2, nullptr);
    }

    bool containKey(int bit) {
        return link[bit] != nullptr;
    }

    void putKey(int bit, Node* node) {
        link[bit] = node;
    }

    Node* getKey(int bit) {
        return link[bit];
    }
};

class Trie {
    Node* root;
public:
    Trie() {
        root = new Node();
    }

    void insert(int num) {
        Node* node = root;
        for (int i = 31; i >= 0; i--) {
            int bit = (num >> i) & 1;
            if (!node->containKey(bit)) {
                node->putKey(bit, new Node());
            }
            node = node->getKey(bit);
        }
    }

    int findMaxXOR(int x) {
        Node* node = root;
        int maxi = 0;
        for (int i = 31; i >= 0; i--) {
            int bit = (x >> i) & 1;
            if (node->containKey(1 - bit)) {
                maxi = (maxi << 1) | 1;
                node = node->getKey(1 - bit);
            } else {
                maxi = (maxi << 1);
                node = node->getKey(bit);
            }
        }
        return maxi;
    }
};

class Solution {
public:
    int findMaximumXOR(vector<int>& nums) {
        ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
        Trie trie;
        for (auto elem : nums) {
            trie.insert(elem);
        }

        int maxi = 0;
        for (auto elem : nums) {
            int temp = trie.findMaxXOR(elem);
            maxi = max(maxi, temp);
        }

        return maxi;
    }
};

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