<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>

string decimal_to_binary(int n){
    bitset<32> num = n;
    string s = num.to_string();
    return s;
}

struct Node{
    Node * links[2];
    bool contains(char ch){
        return links[ch-'0']!=NULL;
    }
    Node *get(char ch){
        return links[ch-'0'];
    }
    void put(char ch,Node * node){
        links[ch-'0'] = node;
    }

};

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

    void insert(string s){
        Node * node = root;
        for(int i=0;i<s.size();i++){
            if(!node->contains(s[i])){
                node->put(s[i],new Node());
            }
            node = node->get(s[i]);
        }
    }

    int getmax(string s){
        Node * node = root;
        int ans = 0;
        for(int i=0;i<s.size();i++){
            if(node->contains((1-(s[i]-'0')) + '0')){
                ans += 1<<(32-i-1);
                node = node->get((1-(s[i]-'0')) + '0');
            }
            else{
                node = node->get(s[i]);
            }
        }
        return ans;
    }

};

class Solution {
public:
    int findMaximumXOR(vector<int>& nums) {

        Trie trie;
        for(auto &it : nums){
            string s=decimal_to_binary(it);
            trie.insert(s);
        }
        int ans = 0;
        for(auto &it : nums){
            string s=decimal_to_binary(it);
            ans = max(ans,trie.getmax(s));
        }
        return ans;

        
    }
};
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