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Project Euler problem 7 - Javascript |
s3klyma
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Posts: 153
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ProjectEuler wrote:
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.
What is the 10001st prime number?
Here is my code
<scblockedript type="text/javascblockedript">
var d = 0;
for(i=0;i<=999999999;i++){
for(a=i;a>=0;a--){ //Is it prime?
if(i%a!=0){
document.write(i+"<br>");
d++;
if(d==10001){ //Alert 10,001st
alert(i);
}
}
}
}
}
</scblockedript>
It's not the most optimized, but it should get the job done.
It doesn't print anything out, and doesn't alert anything.
What am I doing wrong?
"Shut the fuck up and quit being a naive fucktard." - Zephyr_Pure
"Oh is that so? Well fuck my porridge, you've convinced me,
everyone's just really mean to you." - COM
Edited by s3klyma on 23-03-10 02:15 |
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RE: Project Euler problem 7 - Javascript |
define
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My count might be off here, but I see 4 opening braces and 5 closing ones.
Error Console?
If you need to contact me, send me a PM. I will read and/or respond in time. |
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RE: Project Euler problem 7 - Javascript |
korg
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Define is right on the money. Remove one of your closing braces and it will work fine.
I deal in pain, All life I drain, I dominate, I seal your fate.
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RE: Project Euler problem 7 - Javascript |
s3klyma
Member
Posts: 153
Location:
Joined: 02.12.07
Rank: HBH Guru |
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Thanks.
Now it works. But I also figured out that it's faulty.
It doesn't just tell me if the number is prime, it tells
me every time a number lower than 'i' doesn't go evenly
into 'i'.
So here is another idea:
If I set a boolean variable, prime, to true. Then during the
second for loop, I can check if i%a == 0, and if it is, I'll
set prime to false.
So at the end of the loop, if prime is still true, then I'll know
that it's a prime number.
I'll post back when I have a working scblockedript.
Edit:
Also, in the second for loop, I wrote
for(a=i;a>=0;a--)
But then it would also check if i%i == 0,
and if i%1 == 0, and they both would, so it would always
report back non-prime.
Editedit:
This is my current code, and I've triple checked the number of
braces, but still it just freezes firefox. What did I do wrong?
<scblockedript type="text/javascblockedript">
var d = 0;
var prime = true;
while( d < 10002 ){
for(i=3;i<=9999999;i++){
prime = true;
for(a=(i-1);a>=2;a--){
if(i%a==0){
prime = false;
}
}
if( prime == true ){
d++;
document.write(i+"<br>");
}
}
}
alert(d);
</scblockedript>
"Shut the fuck up and quit being a naive fucktard." - Zephyr_Pure
"Oh is that so? Well fuck my porridge, you've convinced me,
everyone's just really mean to you." - COM
Edited by s3klyma on 24-03-10 03:37 |
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RE: Project Euler problem 7 - Javascript |
define
Member
Posts: 201
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Joined: 13.12.08
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s3klyma wrote:
So here is another idea:
If I set a boolean variable, prime, to true. Then during the
second for loop, I can check if i%a == 0, and if it is, I'll
set prime to false.
As long as a is not equal to i and a is not equal to 1, then that probably could work.
You could also probably get far by checking a in the range of 1 to 20, as well as verifying the two conditions above. That should cover a large quantity of prime matches, though you'll have to adjust the range as needed.
s3klyma wrote:
This is my current code, and I've triple checked the number of
braces, but still it just freezes firefox. What did I do wrong?
You assumed that Javascblockedript could handle the type of involved recursion that you're performing. Javascblockedript runs in the memory space of the browser so, when you require a lot of it, it locks it up for a great deal of time. 
Try reducing your primary loop to something much lower than 999999, and try the 20 range suggestion I have above. Adjust higher as needed to obtain the desired result.
Also, if you have any choice at all, I'd suggest against using Javascblockedript.
If you need to contact me, send me a PM. I will read and/or respond in time. |
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RE: Project Euler problem 7 - Javascript |
s3klyma
Member
Posts: 153
Location:
Joined: 02.12.07
Rank: HBH Guru |
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Thank you Define!
I got it after your suggestions :D
Here was the final code
<scblockedript type="text/javascblockedript">
var d = 0;
var prime = true;
for(i=2;i<=200000;i++){
prime = true;
for(a=(i-1);a>=2;a--){
if(i%a==0){
prime = false;
}
}
if( prime == true ){
d++;
if(d == 10001){
alert(i);
break;
}
}
}
</scblockedript>
And I will likely go back to using PHP for the challenges, but I got
my php hosting account banned and haven't yet had the chance
to install it locally.
"Shut the fuck up and quit being a naive fucktard." - Zephyr_Pure
"Oh is that so? Well fuck my porridge, you've convinced me,
everyone's just really mean to you." - COM
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RE: Project Euler problem 7 - Javascript |
define
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Posts: 201
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Joined: 13.12.08
Rank: Moderate
Warn Level: 1
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s3klyma wrote:
Thank you Define!
I got it after your suggestions 
No prob, man. Was interesting. Thanks for posting the final code, too.
s3klyma wrote:
And I will likely go back to using PHP for the challenges, but I got
my php hosting account banned and haven't yet had the chance
to install it locally.
Very precise answer.  You've obviously been in the forums before!
If you need to contact me, send me a PM. I will read and/or respond in time. |
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