[Wellington-pm] SEND + MORE = MONEY

[Grant McLean]

On Wed, 2005-03-02 at 09:15 +1300, Finlay Thompson wrote:
> Grant
> 
> I did some guesses on paper and got 10 solutions:
...
> However I think you meant that no two of the numbers {S,E,N,D,M,O,R,Y} 
> should be the same ?

Umm yes, sorry I did omit to say each digit can only be assigned to one
letter.


I came up with a less complicated solution that runs in a little over
half the time of my original ...











































#!/usr/bin/perl -w

use strict;

my $message = 'SEND + MORE = MONEY';

my $letters = join '', sort keys %{{ map { $_, 1} ($message
=~ /([A-Z])/g) }};
my $required = length $letters;

print "$message\n";
solve('', 0..9);

sub solve {
  my $digits = shift;
  
  if(length $digits == $required) {
    $_ = $message;
    eval "tr/$letters/$digits/";
    return if(/\b0/);
    if(/^(....)...(....)...(.....)/) {
      print "$_\n" if($1 + $2 == $3);
    }
    return;
  }

  foreach (1.. at _) {
    my $next = shift;
    solve($digits . $next, @_);
    push @_, $next;
  }
}