Re: [algogeeks] Finding all prime less than 10^8

2010-04-14 Thread Ashish Mishra
The Sieve of Eratosthenes is best for finding prime On Mon, Apr 12, 2010 at 10:58 AM, BlackdiamonD patidarc...@gmail.comwrote: thank kartik thanks but it was with lot of optimized code i was unable to understand though i have changed my code more know it is taking around 8 to 8.5 seconds in

Re: [algogeeks] Finding all prime less than 10^8

2010-04-14 Thread BlackdiamonD
thankx for u r reply.in my code i implemented Sieve of Eratosthenesthat but some type of optimization were required that i have done...got accepted. On Wed, Apr 14, 2010 at 2:57 PM, Ashish Mishra amishra@gmail.comwrote: The Sieve of Eratosthenes is best for finding prime On Mon, Apr

Re: [algogeeks] Finding all prime less than 10^8

2010-04-12 Thread BlackdiamonD
thank kartik thanks but it was with lot of optimized code i was unable to understand though i have changed my code more know it is taking around 8 to 8.5 seconds in my computer but still i am getting TLE on server #includestdio.h #define ten8 (1) const int mod=32; unsigned int

Re: [algogeeks] Finding all prime less than 10^8

2010-04-11 Thread Karthik Reddy
http://wwwhomes.uni-bielefeld.de/achim/prime_sieve.html take a look at this link . The running time is less than 2 sec for 10^8. On Sun, Apr 11, 2010 at 2:38 AM, Black Diamond patidarc...@gmail.comwrote: i have an problem on SPOJ to find all the prime less than 10^8

Re: [algogeeks] Finding all prime less than 10^8

2010-04-11 Thread Qyore wang
Hi, Black DiamonThere is a trick that number that can be devided by 2 or 3 is ignored, so we just deal with number 6n + 1 and 6n + 5, so you can try this: #includecstdio using namespace std; #define ten8 (1) bool M[ten8]; int main() { int half=1, i,j,x=0; int table = 4;

Re: [algogeeks] Finding all prime less than 10^8

2010-04-11 Thread Navin Naidu
Not only even numbers, but you can extend the algorithm for other numbers as well. Start with 2, mark all the numbers which are multiples of 2, then in the next iteration, take 3, and mark all the numbers which are multiples of 3. If a number is already marked, you dont consider that number in

[algogeeks] Finding all prime less than 10^8

2010-04-10 Thread Black Diamond
i have an problem on SPOJ to find all the prime less than 10^8 https://www.spoj.pl/problems/TDPRIMES/ i am using sieve of erastosthenes algorithm to find primes my code is taking in my machine around 10.9 to 11.2 seconds and time limit is 10 second how i can change my code or any diff logic..???

Re: [algogeeks] Finding all prime less than 10^8

2010-04-10 Thread Rohit Saraf
why don't you remove all even numbers from consideration and add 2 explicitly. I think that would help. -- Rohit Saraf Second Year Undergraduate, Dept. of Computer Science and Engineering IIT Bombay http://www.cse.iitb.ac.in/~rohitfeb14 On Sun,