#!/usr/bin/perl -w
use strict;
use Algorithm::Loops qw( NestedLoops );
$| = 1;

my @sum= shift || 20;
my $terms = shift || 4;

print "Ways to get a sum of $sum[0] from $terms unique addends:\n";

my $tries= 0;
my $iter= NestedLoops(
    [ ( sub {
            my $n = @_ ? 1+$_[-1] : 1;
            my $t = $terms - @_;
            my $m = $sum[$#_]/$t-($t-1)/2;
            return [ $n .. int $m ];
    } ) x $terms ],
    {
        OnlyWhen => sub {
            $tries++;
                0 == ( $sum[@_]= $sum[$#_] - $_[-1] )
            &&  $terms == @_;
        },
    },
);
my @cnt;
my $seq= 0;
while(  @cnt= $iter->()  ) {
    printf "%d) %s\n", ++$seq, join ' + ', @cnt
}
print "($tries tries)\n";

[download]

- tye        

In reply to Re: How to restrict partitions (NestedLoops) by tye
in thread How to restrict partitions by crunch_this!

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!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • 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, details, 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, summary, 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.