Beefy Boxes and Bandwidth Generously Provided by pair Networks
XP is just a number
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
    0: #! /usr/local/bin/perl -w
    1: 
    2: use strict;
    3: use warnings;
    4: use diagnostics;
    5: use Data::Dumper;
    6: 
    7: # I found the Sunday Times teaser 2021 interesting enough
    8: # to write a program to solve after I had a few goes on
    9: # paper and kept getting it wrong.
    10: #
    11: # It manages to do what should be a depth first search
    12: # using a simple for loop due to the relative simplicity
    13: # of the search space.
    14: # P.S. There is a prize for sending in the first correct
    15: # answers, but you'll need to have a copy of the ST in
    16: # order to find the address.
    17: #
    18: # Problem taken from Sunday Times 10-Jun-01
    19: #
    20: # Spladders, a game like snakes and ladders, is played
    21: # on a board with spaces numbered 0..N .
    22: # A Player starts at 0, casts the die and moves his
    23: # counter forward the number of squares shown. If he
    24: # lands on a prime, he moves up to the next prime.
    25: # If he lands on a square, he moves down to the next
    26: # lower square (e.g. 25 to 16). Tom and I played a game.
    27: # I went first, and we each threw the die seven times.
    28: # Each time, after Tom threw, his position was double mine
    29: # (and never zero).
    30: #
    31: # What were our positions after seven throws ?
    32: 
    33: my $last = 0;
    34: my $next;
    35: my %primes = ();
    36: 
    37: for (2,3,5,7,11,13,17,19,23,29,31,37,41,43,47)
    38: {
    39:    $primes{$last} = int($_);
    40:    $last = $_;
    41: }
    42: delete $primes{0};
    43: 
    44: my %squares = ();
    45: map {$squares{$_ * $_} = int(($_ - 1) * ($_ - 1))} (1..10);
    46: 
    47: my @posshim = ();
    48: my @possme  = ();
    49: my $start   = 0;
    50: my @carry   = ();
    51: my @record  = (0);
    52: my @all     = ();
    53: my %record  = (0=>[0]);
    54: 
    55: ### roll
    56: 
    57: for (1..7)
    58: {
    59:    roll($_);
    60: }
    61: die "Failed, More than 1 possible sequence"
    62:    if @all > 1;
    63: die "Failed, no possible sequences"
    64:    if @all < 0;
    65: 
    66: print "-------\n\n";
    67: report("My final Sequence",@{$record{$all[0]}});
    68: 
    69: 
    70: #########
    71: 
    72: sub roll
    73: {
    74:    my $roll = shift;
    75:    @carry = @record;
    76:    @record = @all = ();
    77:    report("-----\nRoll $roll",@carry);
    78:    for (@carry)
    79:    {
    80:       my $start    = $_;
    81:       print "Starting with $_\n------\n";
    82:       @possme = MyTry($start);
    83:       @posshim = HisTry($start*2);
    84: 
    85:       report("His possibles        ",@posshim);
    86:       #report("My  possibles",@possme);
    87: 
    88:       my @newme  = carry_me(\@possme, @posshim);
    89:       report("My Matching possibles",@newme);
    90:       for my $val (@newme)
    91:       {
    92:          push(@record,$val) unless grep {$_ == $val} @record;
    93:       }
    94:       record($start,@newme);
    95:    }
    96: }
    97: 
    98: sub record
    99: {
    100:    my $end = shift;
    101:    my @poss = @_;
    102:    my $i;
    103:    my @ref;
    104:    my $found = -1;
    105: 
    106:    #print Data::Dumper->Dump([\%record],["Record"]) , $/;
    107:    for my $poss (@poss)
    108:    {
    109:       my @new = @{$record{$end}};
    110:       push(@new,$poss);
    111:       $record{$poss} = \@new;
    112:       report("Carrying Forward",@new);
    113:       push(@all,$poss);
    114: 
    115:    }
    116:    #print Data::Dumper->Dump([\%record],["Post - Record"]) , $/;
    117: }
    118: 
    119: sub report
    120: {
    121:    my $name = shift;
    122:    my $values = join(', ',@_);
    123:    print "$name => [$values]\n";
    124: }
    125: 
    126: sub HisTry
    127: {
    128:    my $start = shift;
    129:    my @poss  = ();
    130:    for my $die (1..6)
    131:    {
    132:       my $mid = $start + $die;
    133:       my $new = move($start,$die);
    134:       $new = move($start,$die);
    135:       my $valid = validHim($new);
    136:       #print "Him => $start + $die => $mid => $new $valid\n";
    137:       push(@poss,$new) if $valid;
    138:    }
    139:    return @poss;
    140: }
    141: 
    142: sub MyTry
    143: {
    144:    my $start = shift;
    145:    my @poss  = ();
    146:    for my $die (1..6)
    147:    {
    148:       my $mid = $start + $die;
    149:       my $new = move($start,$die);
    150:       $new = move($start,$die);
    151:       my $valid = validMe($new);
    152:       #print "Me  => $start + $die => $mid => $new $valid\n";
    153:       push(@poss,$new) if $valid;
    154:    }
    155:    return @poss;
    156: }
    157: 
    158: sub carry_me
    159: {
    160:   my $ref = shift;
    161:   my @him = @_;
    162:   my @new = ();
    163:   for my $value (@$ref)
    164:   {
    165:      push(@new,$value) if grep {$value*2 == $_} @him;
    166:   }
    167:   return @new;
    168: }
    169: 
    170: sub validHim
    171: {
    172:    my $value = shift;
    173:    return 0 if $value % 2;
    174:    return 0 if $value == 0;
    175:    return 1;
    176: }
    177: 
    178: sub validMe
    179: {
    180:    my $value = shift;
    181:    return 0 if $value == 0;
    182:    return 1;
    183: }
    184: 
    185: sub move
    186: {
    187:    my $old = shift;
    188:    my $roll = shift;
    189:    my $new = $old + $roll;
    190:    $new = $primes{$new} if defined($primes{$new});
    191:    $new = $squares{$new} if defined($squares{$new});
    192:    return int($new);
    193: }
    

In reply to Solver for Sunday Times teaser 2021 by Brovnik

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others avoiding work at the Monastery: (9)
    As of 2015-07-05 15:47 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (67 votes), past polls