<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 {
public:
    int findMaximumXOR(vector<int>& nums) {
        int ans=0;
        int c=1;
        vector<vector<int>> node(1, vector<int> (2,-1));
        for(auto k: nums){
            int x=0;
            for(int i=31;i>=0;i--){
                if((k>>i)&1){
                    if(node[x][1]==-1){
                        node.push_back(vector<int> (2,-1));
                        node[x][1]=c++;
                    }
                    x=node[x][1];
                }
                else{
                    if(node[x][0]==-1){
                        node.push_back(vector<int> (2,-1));
                        node[x][0]=c++;
                    }
                    x=node[x][0];
                }
            }
        }
        for(auto k: nums){
            int val=0;
            int x=0;
            for(int i=31;i>=0;i--){
                if((k>>i)&1){
                    if(node[x][0]==-1){
                        x=node[x][1];
                    }
                    else{
                        val|=(1<<i);
                        x=node[x][0];
                    }
                }
                else{
                    if(node[x][1]==-1){
                        x=node[x][0];
                    }
                    else{
                        val|=(1<<i);
                        x=node[x][1];
                    }
                }
            }
            ans=max(ans,val);
        }
        return ans;
    }
};
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