# Winners Announced for Apprentice Problem 2, Sums of Consecutive Primes, for Threading Challenge 2011

## Winners Announced for Apprentice Problem 2, Sums of Consecutive Primes, for Threading Challenge 2011

Apprentice Level Problem Set 2 (P1:A2) Sums of Consecutive Primes Key Scoring Principles

Basic scoring principles used for the contest entries judging are described at the official rules page. Here is a short summary: each contest entry was scored according to the following criteria: 1) up to 100 points for solutions performance (speed); 2) a maximum of 25 bonus points for a contestants activity in the forum, calculated as 5 bonus points for each valid forum post/reply.

In addition to that judges decided to reward the most correct contest entries. Successful solutions which found all the possible combinations of consecutive prime number sets and perfect powers got up to 60 points for solutions correctness.

Input Data Sets Used for Performance Scoring

Six different input data sets were used to compute the execution score for this problem. Each data set defined as a range to find prime numbers and a maximal power to compute perfect powers. Here is the list of data sets used for performance scoring (start and end of the range, max power):

2 104567 8

1045 80337 6

250 60075 7

2003 30003 14

5065 40024 5

10004 70004 3

Points in Performance Scoring

Each input data set was judged individually. The weights of data sets used in performance scoring were equivalent. The overall performance score was calculated as a sum of all six input data sets individual performance.

We allowed a total of 600 seconds (10 minutes) execution maximum for each input set; for those runs that took longer than 600 seconds or had runtime errors during execution, zero performance points were awarded. Some entries that could not be built on the MTL and those entries that were not able to correctly solve input data set got zero points as well.

Successful contest entries that found all possible number sets in less than 10 minutes were ranked based on their execution time and got performance points according a linear scale.

Only 100% correct entries got performance points.

Correctness points

To reward 100% correct contest entries, 10 correctness points were awarded to the those entries that found all the possible combinations of sums and powers. 5 or 2 incentive correctness points provided to those entries that missed a few combinations, no more than 20 and 200 combinations respectively.

Weve received 32 contest entries in the Apprentice Level Sums of Consecutive Primes problem set.

Only eight entries successfully solved all six input data sets. 16 entries solved one or more data sets. Unfortunately, nine entries were incomplete and therefore unable to solve any test data sets.

All the timings, performance and correctness points are available in the final Sums of Consecutive Primes score table (attached).

Forum Activity and Bonus Points

Additional bonus points were given for contestants forum posts made before the problem entries were closed. Five points per post (maximum 25 points possible) were awarded.

Entry points and penalties.

Each contest entry got 100 entry points. A penalty of 30 points was taken off in case the entry use significant amount of precompiled information (precompiled prime numbers, for example).

Winners

The problem winners based on highest point total are:

1. dotcsw

2. VoVanx86

3. jmfernandez

These three contestants provided the solutions which correctly solved all the input data sets. They also had the fastest overall code execution and significant bonus points for activity in the contest forum.