| [ QuizWit ] in KIDS 글 쓴 이(By): pomp (PUZZLIST) 날 짜 (Date): 2001년 3월 20일 화요일 오전 10시 52분 54초 제 목(Title): Re: 겹치지 않는 무한 문자열 모범 답안입니다. :) : From: r.e.s. (rs.1@mindspring.com) : Subject: Re: Sequence of A,B,C : Newsgroups: rec.puzzles : Date: 2001-03-07 01:58:07 PST : : <jdallen2000@yahoo.com> wrote ... : | : | Find an infinite sequence of the symbols A,B,C : | such that no two adjacent subsequences are identical. : The "ternary Thue-Morse sequences" give six solutions. : : Start with "A" and iterate the replacement scheme : A -> ABC, B -> AC, C -> B: : : A : ABC : ABC AC B : ABC AC B ABC B AC : ABC AC B ABC B AC ABC AC B AC ABC B : : etc etc : : This gives the sequence : ABCACBABCBACABCACBACABCB... : : (The six possible permutations of ABC lead to five : other solutions by appropriate letter-substitutions.) : : --r.e.s. ----- http://i.am/puzzlist |