10229 - Modular Fibonacci

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akdwivedi
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Posts: 2
Joined: Mon Jun 26, 2006 8:17 am

10229 :WA.....I am angry now !!!

Hi !! here is my code , I am getting wrong answer ..can anybody help me.......

what is wrong ??

#include<iostream>
#include<cstdio>
#include<math.h>
using namespace std;
long long int Fib(long long int n)
{
long long int i=1,h=1;
long long int j =0,k=0,t;
while (n > 0) {
if (n%2 == 1) {
t = j*h;
j = i*h + j*k + t;
i = i*k + t;
}
t = h*h;
h = 2*k*h + t;
k = k*k + t;
n=(int)floor(n/2.0);
}
return j;
}
int main()
{
long long int n,m;
while(scanf("%lld%lld",&n,&m)!=EOF)
{
printf("%lld\n",Fib(n)%((int)pow(2,m)));
}
return 0;
}

even this algo is work on O(lon(n));;;;.....reaply.. soon

thanks..
Programming...

898989
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Posts: 83
Joined: Wed Feb 01, 2006 12:59 pm
Location: (Fci-cu) Egypt
Contact:
Salamo Aleko
You can visit steven halim site for uva problem solving
And find the implemenation in his explantation
I used it and get ac in 10 minutes.
Sorry i do not know a reference. If you got a link..give it to us.
Sleep enough after death, it is the time to work.

joy
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Posts: 48
Joined: Wed Oct 18, 2006 1:00 pm
Contact:
I got WA.....
plz give me some input/ output.....
here is my code:

Code: Select all

``remove after ACC``

plz help..........
Last edited by joy on Fri Dec 22, 2006 7:15 pm, edited 1 time in total.
form kisui na ... class tai asol....
iF U hv d class u get the form....

Jan
Guru
Posts: 1334
Joined: Wed Jun 22, 2005 10:58 pm
Contact:
Check the samples...

Input:

Code: Select all

``````288 6
15006 1
22929 1
4596 1``````
Output:

Code: Select all

``````0
0
0
0``````
Hope these help.
Ami ekhono shopno dekhi...
HomePage

joy
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Posts: 48
Joined: Wed Oct 18, 2006 1:00 pm
Contact:
thanks Jane ...

I got ACC now
Last edited by joy on Fri Jan 26, 2007 1:47 pm, edited 1 time in total.
form kisui na ... class tai asol....
iF U hv d class u get the form....

jojo
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Posts: 2
Joined: Mon Jul 24, 2006 2:36 pm
Location: Poland
Hi
Could anyone tell me how to solve tihs problem ?
I've got our Fn by using O(lg) algorithm and I know that
(a*b*c)%n==((a%n)*(b%n)*(c%n))%n
but I don't know how to use it?
Should I find prime factors of this number and use them to calculate Fn%m - I think that 2147483647th fibbonacii is too big for doing this .
I'm confused.
plx help me
jojo
"Don't let the system get you down!"

joy
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Posts: 48
Joined: Wed Oct 18, 2006 1:00 pm
Contact:
jojo wrote:Hi
Could anyone tell me how to solve tihs problem ?
I've got our Fn by using O(lg) algorithm and I know that
(a*b*c)%n==((a%n)*(b%n)*(c%n))%n
but I don't know how to use it?
Should I find prime factors of this number and use them to calculate Fn%m - I think that 2147483647th fibbonacii is too big for doing this .
I'm confused.
plx help me
jojo
hi,

Code: Select all

``````Sequence of Fibonacci numbers:
Fibo(i)   : 1 1 2 3 5 8 13 21 34 55 89 144 233...
Sequence of Fibonacci numbers mod 2:
Fibo(i)%2 : 1 1 0 1 1 0 1 1 0...
Sequence of Fibonacci numbers mod 3:
Fibo(i)%3 : 1 1 2 0 2 2 1 0 1 1 2 0...``````
You dont need to use n time loop to solve this problem

Hope it helps..
form kisui na ... class tai asol....
iF U hv d class u get the form....

code_man
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Posts: 4
Joined: Tue Jan 16, 2007 6:07 pm

10229 runtime error

I have runtime error, but I don't know why? Somebody can tell me what's wrong with this code? :

Code: Select all

``````#include<iostream>
using namespace std;

int fibon(int a);
int potega(int b);

int main()
{
int n, m;
while(cin>>n>>m)
{ cout<<fibon(n)%potega(m)<<"\n"; }
}
/*****************************************************/
int fibon(int a)
{
if(a==0) return 0;
if(a<1)  return 1;
else
return (fibon(a-1)+ fibon(a-2));
}

int potega(int b)
{
int pomoc=1;
for(int i=0; i<b; i++)
{ pomoc*=2; }

return pomoc;
}``````

newton
Experienced poster
Posts: 162
Joined: Thu Jul 13, 2006 7:07 am
Contact:
i cant find the point like jojo.
may you help explaining it elaborately....

thanx
Last edited by newton on Sun Jul 22, 2007 1:30 pm, edited 1 time in total.

mf
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Location: Zürich, Switzerland
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ifox
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Posts: 1
Joined: Sat Sep 08, 2007 4:56 am
yes, long long will get ac

wyvmak wrote:at a rough scan on your code, what i think is, there seems not a need to use long double, you can make it to int, or long long. then, your program may be better, at least need not worry about floating point error. though i cannot tell you whether it will get AC

fR0D
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Joined: Mon Feb 11, 2008 5:59 am
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Re: 10229 - Modular Fibonacci

can somebody please point out why am i getting WA?

Code: Select all

``````#include<iostream>
using namespace std;

long long p;

long long pow(int i,int j)
{
long long val=1;
int k;
for (k=1;k<=j;k++)
val=val*i;
return val;
}

long long conquer_fibonacci(long long n)
{
long long i,h,j,k,t;
i=h=1;
j=k=0;
while(n>0)
{
if(n%2==1)
{
t=j*h;
j=((i*h)%p + (j*k)%p +t%p)%p;
i=i*k + t;
}
t=h*h;
h=2*k*h + t;
k=k*k + t;
n=(long long) n/2;
}
return j;
}

int main()
{
long long n,res,m;
while(scanf("%lld%lld",&n,&m)!=EOF)
{
p=pow(2,m);
res=conquer_fibonacci(n);
printf("%lld\n",res%pow(2,m));
}
return 0;
}
``````

helloneo
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Posts: 516
Joined: Mon Jul 04, 2005 6:30 am
Location: Seoul, Korea

Re: 10229 - Modular Fibonacci

fR0D wrote:can somebody please point out why am i getting WA?
Sometimes k and t can be very big.. so it may cause overflow error..

fR0D
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Joined: Mon Feb 11, 2008 5:59 am
Contact:

Re: 10229 - Modular Fibonacci

so how can i avoid that???

carliros
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Posts: 6
Joined: Wed Aug 13, 2008 1:30 am

Input
11 7
11 6
2147483647 2
0 0
2147483647 0
2147483647 19

output
89
25
1
0
0
325917