Comments on: ICPC World Finals: Day 2 http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/ Thoughts, Projects, Happenings, Ideas Sun, 13 May 2012 20:56:46 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Jon http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/comment-page-1/#comment-76 Jon Thu, 13 Apr 2006 06:32:00 +0000 http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/#comment-76 Yeah I know I could use summation formulas but really why write code for that? Plus I have to think back to algebra. EW! Yeah I know I could use summation formulas but really why write code for that? Plus I have to think back to algebra. EW!

]]> By: Colin M http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/comment-page-1/#comment-77 Colin M Thu, 13 Apr 2006 06:10:00 +0000 http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/#comment-77 Well no, it didn't take us 43 minutes... we had to follow this script of submitting a wrong solution, then asking a clarification, getting the response, modifying our code, and finally submitting it correctly so that we would get used to the contest software.<BR/><BR/>Actually, there's two things that you could fix from that implementation (which is roughly what we were told to submit the first time). Here's what I would suggest instead, as our final answer:<BR/><BR/>long sum;<BR/><BR/>if (N <= 0)<BR/> sum = 1 - (-N)*(-N+1)/2;<BR/>else<BR/> sum = N*(N+1)/2;<BR/><BR/>a) constant-time algorithm<BR/>b) handles N <= 0 Well no, it didn’t take us 43 minutes… we had to follow this script of submitting a wrong solution, then asking a clarification, getting the response, modifying our code, and finally submitting it correctly so that we would get used to the contest software.

Actually, there’s two things that you could fix from that implementation (which is roughly what we were told to submit the first time). Here’s what I would suggest instead, as our final answer:

long sum;

if (N < = 0)
sum = 1 – (-N)*(-N+1)/2;
else
sum = N*(N+1)/2;

a) constant-time algorithm
b) handles N <= 0

]]> By: Jon http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/comment-page-1/#comment-78 Jon Wed, 12 Apr 2006 16:28:00 +0000 http://www.mccambridge.org/blog/2006/04/icpc-world-finals-day-2/#comment-78 It took you 43 minutes to write:<BR/>int sum = 0;<BR/>for(int i = 1 ; i <= N ; i++) {<BR/> sum += i;<BR/>}<BR/><BR/>return sum;<BR/><BR/>I really hope I misunderstood your problem since this just took me about 1 second (I'm a slow typer).<BR/><BR/>Well it sounds like you're having a lot of fun and I now regret I didn't make it to their info session/first practice. To bad I can't ever do it now. It took you 43 minutes to write:
int sum = 0;
for(int i = 1 ; i < = N ; i++) {
sum += i;
}

return sum;

I really hope I misunderstood your problem since this just took me about 1 second (I’m a slow typer).

Well it sounds like you’re having a lot of fun and I now regret I didn’t make it to their info session/first practice. To bad I can’t ever do it now.

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