REX - RegExp Master

no tags 

You are given a set of 10 tasks. For each of these tasks you must write the correct Regular Expression of minimal size in C format (current SPOJ version). Each regular expression will be tested against a special test set, which contains right and wrong strings. The expression which is composed by you must correctly work on all test cases.

Task 1 You are to write regular expression which determines if a given string is equal to "abcdefghijklmnopqrstuv18340" or not.

Example of correct strings:
abcdefghijklmnopqrstuv18340
Example of wrong strings:
abcdefghijklmnoasdfasdpqrstuv18340

Task 2 You are to write a regular expression which determines whether a given string is a GUID, with or without brackets. Here GUID is a string, consisting of 8, 4, 4, 4, 12 hex digits separated by '-'.

Examples of correct strings:
{e02fa0e4-01ad-090A-c130-0d05a0008ba0}
e02fd0e4-00fd-090A-ca30-0d00a0038ba0


Examples of wrong strings:
02fa0e4-01ad-090A-c130-0d05a0008ba0}
e02fd0e400fd090Aca300d00a0038ba0


Task 3 You are to write a regular expression which determines whether the given string is a valid MAC-address.

Examples of correct strings:
01:32:54:67:89:AB
aE:dC:cA:56:76:54


Examples of wrong strings:
01:33:47:65:89:ab:cd
01:23:45:67:89:Az


Task 4 You are to write a regular expression which determines whether a given string is uppercase and sorted in non-descending order.

Examples of correct strings:
AABCD
ABCDZ


Examples of wrong strings:
aABCD
ZABCD


Task 5 You are to write a regular expression which determines whether a given string is the hex identification of a color in HTML. Here #FFFFFF stands for white, #000000 for black, #FF0000 for red, etc.

Examples of correct strings:
#FFFFFF
#FF3421
#00ff00


Examples of incorrect strings:
232323
f#fddee
#fd2


Task 6 You are to write a regular expression which determines whether the given string is a date in dd/mm/yyyy format. The date is in the range from the year 1600 to the year 9999.

Examples of correct strings:
29/02/2000
30/04/2003
01/01/2003


Examples of wrong strings:
29/02/2001
30-04-2003
1/1/1899


Task 7 You are to write a regular expression which determines whether the given string is a valid e-mail address with respect to RFC number 2822

Examples of correct strings:
mail@mail.ru
valid@megapochta.com
aa@aa.info


Examples of wrong strings:
bug@@@com.ru
@val.ru
Just Text2
val@val
val@val.a.a.a.a
12323123@111[]][]


Task 8 You are to write a regular expression which determines whether the given string is an IP address, in decimal format

Examples of correct strings:
127.0.0.1
255.255.255.0
192.168.0.1


Examples of wrong strings:
1300.6.7.8
abc.def.gha.bcd
254.hzf.bar.10


Task 9 You are to check whether a given password is strong. A password is said to be strong if it consists of 8 and more symbols, where a symbol is one from the set: English letter, digit or underline. Additionally, a strong password must contain at least one uppercase letter, at least one lowercase letter and at least one digit.

Examples of correct strings:
C00l_Pass
SupperPas1


Examples of wrong strings:
Cool_pass
C00l


Task 10 You are to write a regular expression which determines whether a given string is a six-digit positive integer, printed in decimal format without leading zeros.

Examples of correct strings:
123456
234567


Examples of wrong strings:
1234567
12345


For testing we use the following C-function:

int match(const char *string, char *pattern)
{
    int status;
    regex_t re;

    if (regcomp(&re, pattern, REG_EXTENDED|REG_NOSUB) != 0) {
        return(0);
    }
    status = regexec(&re, string, (size_t) 0, NULL, 0);
    regfree(&re);
    if (status != 0) {
        return (0);
    }
    return (1);
}

Input

There is no input data for this problem

Output

Output your answer as a set of 10 lines. The first line is for the first task, the second line for the second task, etc. All other lines will be ignored. If you don't want to solve some task, then in the corresponding line output "---". Otherwise, output the regular expression for this task. If any of your regular expressions are invalid you'll get Wrong Answer status.

Score

For each solved task you'll get exactly 1 point plus a bonus points equal to 1/(regular expression size).

Example

Output:
---
^[1-9]{1}[0-9]{3} ?[A-Z]{2}$
---
---
---
---
---
---
---
---

It's just an example of what output data should look like. If the answer for second task were right, then you would get 1 + 1/28 = 1.035714 points.


hide comments
Mitch Schwartz: 2013-02-07 03:35:14

Task 7 is severely broken: val@val.a.a.a.a is a valid email address according to RFC number 2822, so solvers must make blind guesses as to what the problem setter had in mind. Edit: Even with http://www.spoj.com/forum/viewtopic.php?f=47&t=4455 , description is horrible, I can't guess it. What are the allowed characters? Are two "." in a row allowed on left side? Which segments of right side must have at least two characters?

Task 6 a little unclear: "The date is in the range from the year 1600 to the year 9999." -- it could mean we should reject dates before 1600, or that such dates are guaranteed not to appear in test suites. Edit: Seems we must reject those dates.

Aside from that I suspect some element of "guess the weaknesses in test suites" is involved in getting the very best scores here; maybe that's why it's in tutorial instead of challenge? Edit: Suspicion confirmed, I got AC with shorter, incorrect regexes.

Task 9: Lack of lookaround in this flavor of regex makes it awkward and a bit interesting; if my analysis is correct then 9099 characters is possible for a correct solution using "simple" setup, and a bit less using more complicated ones; but the test data seems especially weak for it, so it's "better" not to use a correct solution.

The problem definitely is not good enough for challenge section, although the concept is nice. It could be retitled "Guessing Master".

Last edit: 2013-02-07 18:17:50

Added by:Roman Sol
Date:2007-07-31
Time limit:0.100s
Source limit:10000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:TEXT
Resource:ZCon 2008