<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>

template <typename IntegerType = int, int INT_SIZE = 31, int capacity = 5000000>
struct BinaryTrie {
    int nxt[capacity][2]{}, freq[capacity]{}, nodesCount;

    BinaryTrie() {
        nodesCount = 0;
    }

    void add(const IntegerType& x) {
        int node = 0;
        for (int i = INT_SIZE; i >= 0; --i) {
            bool bit = (x >> i) & 1;

            if (nxt[node][bit] == 0)
                nxt[node][bit] = ++nodesCount;

            node = nxt[node][bit];
            ++freq[node];
        }
    }

    void erase(const IntegerType& x) {
        int node = 0;
        for (int i = INT_SIZE; i >= 0; --i) {
            bool bit = (x >> i) & 1;
            node = nxt[node][bit];
            --freq[node];
        }
    }

    IntegerType getMin(const IntegerType& x) {
        IntegerType res = 0;
        int node = 0;
        for (int i = INT_SIZE; i >= 0; --i) {
            bool bit = (x >> i) & 1;
            if (nxt[node][bit] != 0 && freq[nxt[node][bit]]) {
                node = nxt[node][bit];
            }
            else {
                node = nxt[node][bit ^ 1];
                res |= (1LL << i);
            }
        }

        return res;
    }

    IntegerType getMax(const IntegerType& x) {
        IntegerType res = 0;
        int node = 0;
        for (int i = INT_SIZE; i >= 0; --i) {
            bool bit = (x >> i) & 1;
            if (nxt[node][bit ^ 1] != 0 && freq[nxt[node][bit ^ 1]]) {
                node = nxt[node][bit ^ 1];
                res |= (1LL << i);
            }
            else {
                node = nxt[node][bit];
            }
        }

        return res;
    }
};

class Solution {
public:
    int findMaximumXOR(vector<int>& nums) {
        if (nums.size() == 1) return 0;
        BinaryTrie bt;
        int ans = 0;

        for (const int& i : nums) {
            bt.add(i);
        }

        for (const int& i : nums) {
            ans = max(ans, bt.getMax(i));
        }

        return ans;
    }
};
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