Prime Number Programs
All these programs use brute force to find the possible primes, or find if a certain number is prime or composite by checking the inputs going up.
The python problem set has a double loop, full recursion, and a loop and recursion for the test case. Using the pypy python executable leads to a much greater speed boost than the default python 2.7 or 3.1 interperters.
C wins the race for speed in this case, and Java is not far behind pypy.