<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>

#define ll long long
class Solution {
public:
    int findMaximumXOR(vector<int>& nums) {
        ll m = nums.size();
        vector<ll> f;
        f.push_back(0);
        f.push_back(0);
        ll n = 0;
        vector<vector<ll> > trie;
        trie.push_back(f);
        for(ll i=0; i<m; i++){
            ll cur = 0;
            ll x = nums[i];
            for(ll j=31; j>=0; j--){
                if(x&(1<<j)){
                    if(trie[cur][1]!=0){
                        cur = trie[cur][1];
                    }else{
                        n++;
                        trie[cur][1] = n;
                        cur = n;
                        trie.push_back(f);
                    }
                }else{
                    if(trie[cur][0]!=0){
                        cur = trie[cur][0];
                    }else{
                        n++;
                        trie[cur][0] = n;
                        cur = n;
                        trie.push_back(f);
                    }

                }
            }
        }
        // for(ll i=0; i<=n;i++){
        //     cout<<trie[i][0]<<" "<<trie[i][1]<<"\n";
        // }
        ll ans = 0;
        for(ll i=0; i<m; i++){
            ll cur = 0;
            ll y = 0;
            ll x = nums[i];
            for(ll j=31; j>=0; j--){
                if(x&(1<<j)){
                    if(trie[cur][0]!=0){
                        y += (1<<j);
                        cur = trie[cur][0];
                    }else{
                        cur = trie[cur][1];
                    }
                }else{
                    if(trie[cur][1]!=0){
                        y += (1<<j);
                        cur = trie[cur][1];
                    }else{
                        cur = trie[cur][0];
                    }
                }
            }
            // cout<<x<<" "<<y<<"\n";
            ll e = x ^ y;
            ans = fmax(ans,y);
        }
        return ans;
    }
};
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