Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site alice.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!alice!ark From: ark@alice.UucP (Andrew Koenig) Newsgroups: net.puzzle Subject: Re: 5 boxes Message-ID: <4928@alice.UUCP> Date: Sun, 2-Feb-86 13:19:49 EST Article-I.D.: alice.4928 Posted: Sun Feb 2 13:19:49 1986 Date-Received: Mon, 3-Feb-86 05:03:56 EST References: <1146@ecsvax.UUCP> Organization: Bell Labs, Murray Hill Lines: 23 > _____1____________2____ > | | | > 3| 4| 5| > |___6____7__|__8_____9__| > | | | | > 10| 11| 12| 13| > |______|_________|______| > 14 15 16 The problem as shown has no solution. Consider: if all these cells are to be traversed by a single line, then except for the ends of the line, the line must leave every cell it enters. Thus no more than two cells may have an odd number of entrances, and if exactly two do then the line must begin in one and end in the other. In this diagram, FOUR cells have an odd number of entrances: 1 3 4 6 7 2 4 5 8 9 7 8 12 15 11 1 2 5 13 16 15 14 10 3 (in other words, the outside) Hence, no legitimate solutions.