<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 Solution {
    struct TrieNode{
        int mini;
        TrieNode* next[2];

        TrieNode(){
            mini=INT_MAX;
            next[0]=next[1]=NULL;
        }
    };

    class Trie{
        TrieNode *root;

    public:
        Trie(){
            root=new TrieNode();
        }

        void insert(int a){
            TrieNode *temp=root;
            for(int i=30;i>=0;i--){
                int bit=(((1<<i)&a)!=0);
                if(temp->next[bit]==NULL) temp->next[bit]=new TrieNode();
                temp=temp->next[bit];
                temp->mini=min(temp->mini,a);
            }
        }

        int find(int x){
            int ans=0;
            TrieNode *temp=root;
            for(int i=30;i>=0;i--){
                int xbit=(((1<<i)&x)!=0);
                int prefbit=(!xbit);
                if(temp->next[prefbit]!=NULL){
                    ans+=(1<<i);
                    temp=temp->next[prefbit];
                }
                else if(temp->next[!prefbit]!=NULL){
                    temp=temp->next[!prefbit];
                }
                else{
                    ans=0;
                    break;
                }
            }
            return ans;
        }
    };

public:
    int findMaximumXOR(vector<int>& nums) {
        int ans=0;
        Trie tr;
        for(auto i:nums) tr.insert(i);
        for(auto i:nums) ans=max(ans,tr.find(i));
        return ans;
    }

    Solution(){
        ios_base::sync_with_stdio(false);
    }
};
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