Problem - Maximum XOR of Two Numbers

Given an integer array nums, return the maximum result of nums[i] XOR nums[j]. Example: For $[3, 10, 5, 25, 2, 8]$, the maximum XOR is $28$ ($5 \oplus 25 = 28$).

Naive approach: try all pairs in $O(n^2)$. The trie approach: store numbers as binary strings in a trie.

For each number, traverse the trie trying to go the opposite direction at each bit (maximizing XOR). Constraints: $1$ to $2 \cdot 10^5$ numbers, each from $0$ to $2^{31} - 1$.