<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>

struct Node {
    Node* children[2] = {nullptr, nullptr};
};

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

    string binaryForm(int n) {
        return bitset<32>(n).to_string(); 
    }

    int binaryToDecimal(const string &binary) {
        return stoi(binary, nullptr, 2);
    }
    
    int findMaximumXOR(vector<int>& nums) {
        // Insert numbers into Trie
        for (int num : nums) {
            Node* droot = root;
            string binary = binaryForm(num);
            for (char c : binary) {
                int bit = c - '0';
                if (droot->children[bit] == nullptr) {
                    droot->children[bit] = new Node();
                }
                droot = droot->children[bit];
            }
        }

        // Find maximum XOR
        int maxx = 0;
        for (int num : nums) {
            string o = binaryForm(num);
            string s = o;
            Node* droot = root;

            // Toggle bits in `s` for potential max XOR
            for (int j = 0; j < s.length(); j++) { 
                s[j] = (s[j] == '1') ? '0' : '1';
            }

            for (int j = 0; j < s.length(); j++) {
                int x = s[j] - '0';
                if (droot->children[x] != nullptr) {
                    droot = droot->children[x];
                } else {
                    s[j] = (x == 1) ? '0' : '1'; 
                    droot = droot->children[s[j] - '0'];
                }
            }

            maxx = max(maxx, binaryToDecimal(o) ^ binaryToDecimal(s));
        }
        return maxx;
    }
};
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