Re: Solve - takes very long time
- To: mathgroup at smc.vnet.net
- Subject: [mg121855] Re: Solve - takes very long time
- From: DrMajorBob <btreat1 at austin.rr.com>
- Date: Wed, 5 Oct 2011 04:00:23 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <j6bris$8m4$1@smc.vnet.net> <201110040530.BAA20723@smc.vnet.net>
- Reply-to: drmajorbob at yahoo.com
The conditions #[[2]] < #[[5]] and #[[3]] < #[[6]] do not belong, however. Bobby On Tue, 04 Oct 2011 00:30:53 -0500, Ray Koopman <koopman at sfu.ca> wrote: > On Oct 3, 1:26 am, Fredob <fredrik.dob... at gmail.com> wrote: >> Hi, >> >> I tried the following on Mathematica 8 and it doesn't seem to stop >> running (waited 40 minutes on a 2.6 Ghz processor w 6 GB of primary >> memory). >> >> Solve[ >> {100*Subscript[x, 2] + 10*Subscript[x, 1] + Subscript[x, 0] + >> 100*Subscript[y, 2] + 10*Subscript[y, 1] + Subscript[y, 0] == >> 100*Subscript[z, 2] + 10*Subscript[z, 1] + Subscript[z, 0], >> Subscript[x, 0] > 0, Subscript[y, 0] > 0, Subscript[z, 0] > 0, >> Subscript[x, 1] > 0, Subscript[y, 1] > 0, Subscript[z, 1] > 0, >> Subscript[x, 2] > 0, Subscript[y, 2] > 0, Subscript[z, 2] > 0, >> Subscript[x, 0] <= 9, Subscript[y, 0] <= 9, Subscript[z, 0] <= 9, >> Subscript[x, 1] <= 9, Subscript[y, 1] <= 9, Subscript[z, 1] <= 9, >> Subscript[x, 2] <= 9, Subscript[y, 2] <= 9, Subscript[z, 2] <= 9, >> Subscript[x, 0] != Subscript[y, 0] != Subscript[z, 0] != >> Subscript[x, 1] != Subscript[y, 1] != Subscript[z, 1] != >> Subscript[x, 2] != Subscript[y, 2] != Subscript[z, 2]}, >> {Subscript[x, 2], Subscript[y, 2], Subscript[z, 2], Subscript[x, 1], >> Subscript[y, 1], Subscript[z, 1], Subscript[x, 0], Subscript[y, 0], >> Subscript[z, 0] }, >> Integers] >> >> The problem was a homework for my daugther where you are supposed to >> use all digits to build - but only once - 2 three digit numbers and >> addition. > > For each of the 42 solutions found by the brute force search given > below there are seven other solutions that may be obtained by > interchanging x0,y0 and/or x1,y1 and/or x2,y2. > > FromDigits/@Partition[#,3]& /@ Select[Permutations@Range@9, > #[[1]] < #[[4]] && #[[2]] < #[[5]] && #[[3]] < #[[6]] && > #.{100,10,1,100,10,1,-100,-10,-1} == 0 &] > > {{124,659,783}, {125,739,864}, {127,359,486}, > {127,368,495}, {128,439,567}, {134,658,792}, > {142,596,738}, {142,695,837}, {143,586,729}, > {152,487,639}, {152,784,936}, {162,387,549}, > {162,783,945}, {173,286,459}, {173,295,468}, > {182,394,576}, {182,493,675}, {214,569,783}, > {214,659,873}, {215,478,693}, {215,748,963}, > {216,378,594}, {216,738,954}, {218,349,567}, > {218,439,657}, {234,657,891}, {235,746,981}, > {241,596,837}, {243,576,819}, {243,675,918}, > {251,397,648}, {271,593,864}, {271,683,954}, > {281,394,675}, {314,658,972}, {317,529,846}, > {317,628,945}, {324,567,891}, {324,657,981}, > {341,586,927}, {342,576,918}, {352,467,819}} > -- DrMajorBob at yahoo.com
- References:
- Re: Solve - takes very long time
- From: Ray Koopman <koopman@sfu.ca>
- Re: Solve - takes very long time