Practice · 3 of 3
Signal Pairing
CHALLENGE
Difficulty: advanced+25 XP
**Problem.** Given n device ids, print the maximum value of a[i] xor a[j] over all pairs i < j. **Constraints:** 1 <= n <= 200000; 0 <= a[i] < 2^30. The all-pairs scan is the classic near-miss.
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