UNSW ProgComp: Problem 5 - 2008

<?php

$input = <<<END
416 12 4
So Isaac dwelt in Gerar and the men of the place asked him
of his wife and he said, "She is my sister," for he feared to say
"She is my wife", lest, said he, "the men of the place
should kill me for Rebekah because she was fair to look upon"
and it came to pass when he had been there a long time that Abimelech,
king of the Philistines, looked out at a window and saw, and, behold,
Isaac was sporting with Rebekah his wife and Abimelech called Isaac
and said, "Behold of a surety she is thy wife and how saidst thou
'she is my sister'?" and Isaac said unto him, "Because, I said, lest I
die for her."
Genesis 26:6-9. King James version.
END;

$input = explode("\n", $input);

$input_2 = explode(" ", array_shift($input)); //offset, cycle (distance), length

$input = implode("\n", $input); //return to long string
$input = str_split($input);

$letters = array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z');
$axed_string = str_replace($letters, '', strtolower(implode($input)));
$axed_characters = str_split($axed_string);
$new_input = str_replace($axed_characters, '', $input);

//I'm going to do this the stupid way
if($input_2[1] < 0){
    //going to have to work the other way
    $count = count($input);
    $disp_count = 0;
    $char_count = count($new_input);
    $str_out = null;
    while($count > 0){
        $current = $input[$count];
        $echoed = false;
        if(in_array(strtolower($current), $letters)){
            //current is a letter
            if(($char_count-$input_2[0]-1)%abs($input_2[1]) == 0 && $disp_count < $input_2[2] && $char_count < $input_2[0]+2){
                //display character with [] and add the character to the output string
                $disp_count++;
                $output[] = $current;
                $str_out[] = "[".$current."]";
                $echoed = true;
            }
            $char_count--;
        }
        if(!$echoed){
            $str_out[] = $current;
        }
        $count--;
    }
    $str_out = implode(array_reverse($str_out));
    $output = implode(array_reverse($output));
    echo $str_out;
}else{
    $count = 0;
    $disp_count = 0;
    $char_count = 0;
    while($count < count($input)){
        $current = $input[$count];
        $echoed = false;
        if(in_array(strtolower($current), $letters)){
            //current is a letter
            if(($char_count-$input_2[0]+1)%abs($input_2[1]) == 0 && $disp_count < $input_2[2] && $char_count > $input_2[0]-2){
                //display character with [] and add the character to the output string
                $disp_count++;
                $output .= $current;
                echo "[".$current."]";
                $echoed = true;
            }
            $char_count++;
        }
        if(!$echoed){
            echo $current;
        }
        $count++;
    }
}

echo "\n\n$output";