Non-adjacent Form

The non-adjacent form (NAF) of a number is a unique signed-digit representation. Like the name suggests, non-zero values cannot be adjacent. For example:

(0 1 1 1)2 = 4 + 2 + 1 = 7
(1 0 −1 1)2 = 8 − 2 + 1 = 7
(1 −1 1 1)2 = 8 − 4 + 2 + 1 = 7
(1 0 0 −1)2 = 8 − 1 = 7

All are valid signed-digit representations of 7, but only the final representation (1 0 0 −1) is in NAF.

Read more about Non-adjacent Form:  Obtaining NAF, Properties

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