Oh, I missed that! Something like this then:

#!/usr/lib/perl
use strict;
use warnings;

my $kPoolSpan = 2;
my %hash      = (
    3  => [1 .. 2],
    4  => [2 .. 2],
    6  => [4 .. 5],
    7  => [2 .. 6],
    8  => [1 .. 3],
    11 => [5 .. 10],
    );
my @indexes = sort {$a <=> $b} keys %hash;
my @pool;

while (@indexes) {
    my $oldPoolSize = @pool;

    push @pool, shift @indexes if !@pool;
    push @pool, shift @indexes
        while @indexes && $pool[0] + $kPoolSpan >= $indexes[0];

    my $poolSum;
    my @new = @pool[$oldPoolSize .. $#pool];

    for my $poolEntry (@pool) {
        $poolSum += $_ for @{$hash{$poolEntry}};
    }

    print "Pool @pool sum (added @new): $poolSum\n";
    shift @pool while @indexes && @pool && $pool[0] + $kPoolSpan < $in
+dexes[0];
}

[download]

Prints:

Pool 3 4 sum (added 3 4): 5
Pool 4 6 sum (added 6): 11
Pool 6 7 8 sum (added 7 8): 35
Pool 11 sum (added 11): 45

[download]
True laziness is hard work

In reply to Re^3: How to code this? by GrandFather
in thread How to code this? by BrowserUk

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