<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{
    public:
        Node* left;
        Node* right;
        Node(){
            this->left=this->right=NULL;
        }
};

class Solution {
public:
    int maxXorPair(Node* head, int value){
        int curr_xor=0;
        Node* curr=head;
        for(int i=31;i>=0;i--){
            int bit =(value>>i)&1;
            if(bit==0){
                if(curr->right!=NULL){
                    curr=curr->right;
                    curr_xor+=(1<<i);
                }
                else{
                    curr=curr->left;
                }

            }
            else{
                if(curr->left!=NULL){
                    curr=curr->left;
                    curr_xor+=(1<<i);
                }
                else{
                    curr=curr->right;
                }
            }
        }
        return curr_xor;
    }
    void insert(Node* head,int value){
        Node* curr=head;
        for(int i=31;i>=0;i--){
            int bit=(value>>i)&1;
            if(bit==0){
                if(curr->left==NULL){
                    curr->left=new Node();
                }
                curr=curr->left;
            }
            else{
                if(curr->right==NULL){
                    curr->right=new Node();
                }
                curr=curr->right;
            }
        }
    }

    int findMaximumXOR(vector<int>& nums) {
        Node* head=new Node();
        insert(head,nums[0]);
        int ans=0;
        for(int i=1;i<nums.size();i++){
            int res=maxXorPair(head,nums[i]);
            ans=max(ans,res);
            insert(head,nums[i]);
        }
        return ans;
    }
};
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