<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 Trie{
    vector<Trie*>val;
    public:
    Trie(){
        val.resize(2,NULL);
    }
    void insert(int num, Trie *root){
        Trie*temp = root;
        for(int i=0;i<31;++i){
            bool rem;
            if((1<<(30-i)) & num)rem = 1;
            else rem = 0;
            if(temp->val[rem])temp = temp->val[rem];
            else{
                temp->val[rem] = new Trie();
                temp = temp->val[rem];
            }
        }
    }
    int solve(Trie*root, int num){
        Trie*temp = root;
        int ans = 0;
        for(int i=0;i<31;++i){
            bool rem;
            if((1<<(30-i)) & num)rem = 0;
            else rem = 1;
            // cout<<rem<<" ";
            
            if(temp->val[rem]){
                ans = ans ^ (rem<<(30-i));
                temp = temp->val[rem];
            }
            else{
                ans = ans ^ ((!rem)<<(30-i));
                temp = temp->val[!rem];
            }
        }
        // cout<<endl;
        return ans;
    }
};

class Solution {
public:
Solution(){
        ios_base::sync_with_stdio(false);
        cin.tie(nullptr);
        cout.tie(nullptr);
    }
    int findMaximumXOR(vector<int>& nums) {
        Trie*ans = new Trie();
        int ret = 0;
        for(int i=0;i<nums.size();++i){
            ans->insert(nums[i], ans);
            ret = max(ret, nums[i] ^ (ans->solve(ans, nums[i])));
        }
        return ret;
    }
};
364086