Задача (php)

#!/usr/bin/perl

use strict;
use 5.010;

my @a = (3=>"a", 1=>"b", 2=>"c");
my @b = (1=>"str1-b ", 2=>"str2-c ", 3=>"str3-a ");

my %w = map { $a[$_*2] => $_ } 0..$#a/2;
say sort { $w{($a=~/(\d+)/)[0]} <=> $w{($b=~/(\d+)/)[0]} } values %{{@b}};

$my_array = array(1=>"str1-b ", 2=>"str2-c ", 3=> "str3-a ");

function cmp($a, $b)
{
    $tmp_a = explode("-", $a);
    $tmp_b = explode("-", $b);
    $tmp_a = ord(rtrim($tmp_a[1], " "));
    $tmp_b = ord(rtrim($tmp_b[1], " "));
    if ($tmp_a == $tmp_b) {
        return 0;
    }
    return ($tmp_a < $tmp_b) ? -1 : 1;
}

usort($my_array, "cmp");

var_dump($my_array);

//==============================

array(3) {
  [0]=>
  string(7) "str3-a "
  [1]=>
  string(7) "str1-b "
  [2]=>
  string(7) "str2-c "
}

$a = array(3=>"a", 1=>"b", 2=>"c"); //отсортирован по значению
$b = array(1=>"str1-b ", 2=>"str2-c ", 3=>"str3-a "); //Не отсортирован

foreach ($a as $key => $value)
{
    echo $b[$key] . PHP_EOL;
}

$result = array();
foreach($a as $k => $v)
    $result[] = $b[$k];

echo join(' ', $result);