精彩Gray code

Graycodeisaninterestingcodesequenceandhasmanyapplicationsincomputerscience.Nomatteryouhaveknownitbeforeornot,herearesomeintroductionsaboutitsfeatures:(1)Graycodehas2^nuniqueelements;(2)EachelementcontainsndigitsofOorl;(3)Eachpairofadjacentelementshasexactlyonedifferentdigit.