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How about every value appears 0 mod n times except one which appears 1 mod n times? :) Solution: xor is just addition mod 2. Write the numbers in base n and do
by twiceaday 6mo ago
How about every value appears 0 mod n times except one which appears 1 mod n times? :)
Solution: xor is just addition mod 2. Write the numbers in base n and do digit-wise addition mod n (ie without carry). Very intuitive way to see the xor trick.