<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 *link[2];

    bool containKey(char ch){
        return link[ch-'0']!=NULL;
    }

    void put(char ch,Node *node){
        link[ch-'0']=node;
    }

    Node *get(char ch){
        return link[ch-'0'];
    }

};

class Trie{

    public:

    Node *root;

    Trie(){
        root=new Node();
    }

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

    int maxm(string &word){
        Node *node=root;
        int res=0;
        for(int i=0;i<32;i++){
            if(node->containKey('0'+'0'+1-word[i])){
                res=res|(1<<(31-i));
                node=node->get('0'+'0'+1-word[i]);
            }
            else{
                node=node->get(word[i]);
            }
        }
        return res;
    }
};

string f(int x){
    string s="";
    while(x>0){
        if(x%2==0){
            s.push_back('0');

        }
        else s.push_back('1');
        x/=2;
    }

    while(s.size()<32){
        s.push_back('0');
    }

    reverse(s.begin(),s.end());

    return s;
}

class Solution {
public:
    int findMaximumXOR(vector<int>& v) {
        Trie trie;
        vector<string>x;
        for(auto i:v){
            string z=f(i);
            x.push_back(z);
            trie.insert(z);
        }
        int res=0;
        for(auto i:x){
            res=max(res,trie.maxm(i));
        }
        return res;
    }
};
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