Comment on

Ooh, that is quite elegant indeed. One of my lessons here was "Know in which order thine regex engine tries things" but I completely missed this little optimization. ;) It really matches up temporaly with the spirit of the problem.

I suppose I could also use (?>pattern) to prevent backtracking and perform the greedy match without the negative lookaheads?

(1 x $money) =~ /^(?>(1{10})*)(?>(1{6})*)(?>(1{5})*)(?>(1{1})*)$/
[download]

Although I can't say I've ever really used (?>pattern)...

Anyway, the pain in the butt is counting the number of coins. I like my little (?{$^R+1}) idiom!

blokhead

In reply to Re^2: The greedy change-making problem using regexes by blokhead
in thread The greedy change-making problem using regexes by blokhead

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, 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, 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:
	&		`&`
	<		`<`
	>		`>`
	[		`[`
	]		`]`

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.


Welcome to the Monastery
	PerlMonks