Wrongly asked or am I stupid?

Question

There's a blog post comment on codinghorror.com by Paul Jungwirth which includes a little programming task: You have the numbers 123456789, in that order. Between each number, you must insert either nothing, a plus sign, or a multiplication sign, so that the resulting expression equals 2001. Write a program that prints all solutions. (There are two.) Bored, I thought, I'd have a go, but I'll be damned if I can get a result for 2001. I think the code below is sound and I reckon that there are zero solutions that result in 2001. According to my code, there are two solutions for 2002. Am I right or am I wrong? ``` /** * Take the numbers 123456789 and form expressions by inserting one of '' * (empty string), '+' or '*' between each number. * Find (2) solutions such that the expression evaluates to the number 2001 */ $input = array(1,2,3,4,5,6,7,8,9); // an array of strings representing 8 digit, base 3 numbers $ops = array(); $numOps = sizeof($input)-1; // always 8 $mask = str_repeat('0',…

Accepted Answer

Further down the same page you linked to.... =)

"Paul Jungwirth wrote:

You have the numbers 123456789, in that order. Between each number, you must insert either nothing, a plus sign, or a multiplication sign, so that the resulting expression equals 2001. Write a program that prints all solutions. (There are two.)

I think you meant 2002, not 2001. :)

(Just correcting for anyone else like me who obsessively tries to solve little "practice" problems like this one, and then hit Google when their result doesn't match the stated answer. ;) Damn, some of those Perl examples are ugly.)"

Wrongly asked or am I stupid?

Solution

Problem