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anonymous
 5 years ago
Compare thoughts on Ps1 solutions?
anonymous
 5 years ago
Compare thoughts on Ps1 solutions?

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anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0My stab: # Initialize variables prime_counter = 1 candidate = 3 divisor = 2 while prime_counter < 1000: if candidate%divisor == 0: # for numbers that are not prime candidate += 2 divisor = 2 elif divisor > (candidate/2): # for prime numbers prime_counter += 1 if prime_counter == 1000: print 'Prime #1000 =', candidate candidate += 2 divisor = 2 else: divisor += 1 It works but seems it could be tighter.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I did this some time ago and I'm rather happy with it, although I'm not sure if it was really necessary to print every prime number. prime_candidate = 3 divisor = 2 prime_number = 2 print "2 is prime number 1" while prime_number <= 1000: while prime_candidate%divisor != 0: divisor=divisor+1 if divisor == prime_candidate: print prime_candidate, 'is prime number', prime_number prime_candidate = prime_candidate+2 prime_number = prime_number+1 divisor=2 else: prime_candidate = prime_candidate+2 divisor=2

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Both of these work perfectly. I used lists to get the results working, but my code seems slower than these...I'll rework my original program now, to see if I can improve my code.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I did something very similar to fruiterian. The biggest block for me was figuring out how to reset the divisor after finding a prime. Part 2 of the PS was a piece of cake after getting the first part down.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I tried to use Fermat's little theorem but it doesnt seem to work :S It goes like this: primes=[] n = 0 for p in range (2,150000): if n < 1000: if (2**p2) % p == 0: primes.append(p) n = len (primes) print primes

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0here's what I did, seems to do the trick x = 1 primes = [2] logs = log(primes[0]) goal=1000 while len(primes) < goal: x += 2 pcount = 0 for i in primes: pcount += 1 if x % i == 0: break elif pcount == len(primes): primes.append(x) if len(primes) < goal: logs += log(x) break print ("ratio", logs, " / ", primes[goal1])

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Milo, that's cool, and it works when I run it. Why did you choose the line: elif pcount == len(primes): I've never seen that used as the test of when to stop before.

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i needed a way to divide the new candidate by every one of the existing prime numbers. Since the list f primes was always growing I needed a counter so this seemed to make sense :S

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Oh, that is cool! I actually hadn't noticed you were using the primes listI just thought you were dividing each number by 0len(primes). You could probably stop even earlier, toowhen the current divisor is greater than sqrt(x).

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0OH! duh... I noticed in the Pset they mentioned that at somepoint you could probably stop checking the modulus but I didn't give it too much thought. If I feel ambitious maybe I'll rework my code later tonight :)
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