Phantom's Python Challenge

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Points:30 (partial)
Time limit:4.0s
Memory limit:512M
Author:

Problem type

Allowed languages
Python

After all the ordeal, Christine decided to save your lives by kissing the Phantom. That was very nice of her. However, the Phantom considers letting Christine leave with Raoul, if and only if you can convince him that your party is worthy. He challenges you to write a program that shows all the primes under a specific number, while marking the twin primes. Easy as it may sound, the Phantom is also an expert programmer: you have to prove yourself to be at least as good as him. In Python, he expects you to write it in one statement. This means, no new lines or semi-colons are allowed. To prevent the cheap way of achieving this, you are also not allowed to use eval or exec. To make sure he did not save that scarf for nothing, Raoul bribes you with 30 staggering points.

Input Specification

The input will be one line, containing the number , such that .

Output Specification

All the primes smaller than , separated by whitespace, with a * after every number forming a twin prime with another. A twin prime is defined as a prime number such that or are prime.

Scoring

If your solution is correct and contains only one statement without eval or exec, you get 10 points. For full points, your solution must be at most 160 characters long. More accurately, you get points, capped at 30, where is the length of your solution, if it is correct.

Sample Input

50

Sample Output

2
3*
5*
7*
11*
13*
17*
19*
23
29*
31*
37
41*
43*
47

• Epicnerdking
commented on April 5, 2016 edited
Can we use lambda?

Never mind :), great problem btw!

• GaryZ
commented on April 7, 2015
There goes my evening :P

Thanks for the fun problem, guys!

• FatalEagle
commented on April 7, 2015

Never did I think I would see the day someone actually solves this problem.

• quantum
commented on April 7, 2015

Good job. Now try to make it even shorter!

• GaryZ
commented on April 7, 2015

Too late, I peeked at your code.

• quantum
commented on Dec. 17, 2014
Memory limit increased to 256M

Increased memory limit to 256M. This will allow the problem to be solvable on 64-bit judges.

• quantum
commented on Nov. 30, 2014
Scoring Change

Due to my discovery of an 146 character solution, the old character limit of 220 no longer makes any sense. Therefore, the full score solution now requires 160 characters.

This problem is now out of 30 points so that any old score will not decrease.