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### Thanks

Posted: Wed Jan 30, 2008 6:06 am
Thank you I got Acc......

Posted: Sun Feb 10, 2008 6:28 pm
now i got RE..and most of the cases gives the right answers..And i thought my arithmetic seem no mistakes..I used it and got AC in 369 before..My arithmetic is to calculate the number of the emement of factorial..But it may crash in this case: 9111 1;It will give the wrong answers..i can't find what mistake i have made..i 've confused..help..thanks in advance~

Code: Select all

``````#include <iostream.h>
#include "math.h"

typedef struct
{
int prime;
int num;
}Prime;

bool IfPrime (int n)
{
int limit;

if (n == 2)
return true;
if (n % 2 == 0)
return false;

limit = sqrt (n) + 1;

for (int i = 3; i < limit; i = i + 2)
if (n % i == 0)
return false;
return true;
}

int main ()
{
int n, m;
int i, j, temp;
long long result;
Prime p[6544];
int pNum = 0;

for (i = 0; i <= 65536; i++)
if (IfPrime (i))
p[pNum++].prime = i;

while (cin>>n>>m && n||m)
{
result = 1;
for (i = 1; i < 6544; i++)
p[i].num = 0;

for (i = 2; i <= n; i++)
{
temp = i;

for (j = 1; temp != 1; j++)
{
while (temp % p[j].prime == 0)
{
p[j].num++;
temp = temp / p[j].prime;
}
}
}

for (i = 2; i <= m; i++)
{
temp = i;

for (j = 1; temp != 1; j++)
{
while (temp % p[j].prime == 0)
{
p[j].num--;
temp = temp / p[j].prime;
}
}
}

for (i = 2; i <= n - m; i++)
{
temp = i;

for (j = 1; temp != 1; j++)
{
while (temp % p[j].prime == 0)
{
p[j].num--;
temp = temp / p[j].prime;
}
}
}

for (i = 1; i < 26; i++)
{
for (j = 0; j < p[i].num; j++)
result *= p[i].prime;
}

cout<<result<<endl;
}
return 0;
}``````
[/quote]

Posted: Tue Mar 11, 2008 1:28 pm
my method

test case

Code: Select all

``````110 6
``````

Code: Select all

``````110 * 109 * 108 * 107 * 106 * 105
-------------------------------------------
6 * 5 * 4 * 3 * 2 * 1
``````
you can use 2 matrix or vector to produce them

2.run O(n2) loop to "reduce a fraction" (calculate gcd)

3.the final answer is multiple numerator.

### Re: 530 woes

Posted: Wed Nov 05, 2008 12:16 pm
On this problem i got RE

Code: Select all

``````#include <iostream>
#include <vector>

using namespace std;

int gcd (int u, int v)
{
int t;
while (u>0)
{
if (u<v) {t=u;u=v;v=t;}
u=u-v;
}
return v;
}

int main ()
{
long long double n,m,r,h;
bool first=true;
vector <int> n1,m1;
while (cin>>n>>m)
{
if (n==0 && m==0) break;
if (!first) cout<<endl; else first=false;
r=1;
n1.clear();
m1.clear();
for (int i=n-m+1;i<n+1;i++)
{n1.push_back(i);}
for (int i=2;i<m+1;i++)
{m1.push_back(i);}
for (int i=0;i<n1.size();i++)
{
for (int j=0;j<m1.size();j++)
{
h=gcd(n1[i],m1[j]);
if (n1[i]>1 && m1[j]>1 && h>1)
{
n1[i]/=h;m1[j]/=h;
}
}
}
for (int i=0;i<n1.size();i++) {r*=n1[i];}
cout<<r<<endl;
}
return 0;
}

``````
And can some one say me why do i get WA at 369 because of this. the code is the same except the
cout<<r<<endl; being cout<<n<<" things taken "<<m<<" at a time is "<<r<<" exactly.";

### Re: 530 woes

Posted: Sat May 02, 2009 12:58 am
I'm trying to make the 530, but i get wa!
this is my code
thank you

Code: Select all

``````
#include<iostream>

using namespace std;

int main()
{
int n,m,maior;
long long c;

cin >> n >> m;

while( n != 0 && m != 0)
{
c = 0;
maior = max(m,n-m);

{
}

cout << n <<" things taken "<< m << " at a time is " << (long long)res << " exactly."<< endl;
cin >> n >> m;

}
return 0;
}

``````

### Re: 530 woes

Posted: Sat May 02, 2009 5:54 am
Your code looks like the code of problem 369 not 530

### I need Help on 530(Binomial Showdown)

Posted: Thu Oct 01, 2009 8:35 am
I submitted this code. But got WA. Con u help me?
#include<stdio.h>
long double fact(long double n)
{
if (n==0) return 1;
else return (n*fact(n-1));
}

int main()
{
long double n,k,r,f,g,temp;
while(scanf("%Lf%Lf",&n,&k)==2)
{
long double u=1,l1=1,l2=1;
if(n==0 && k==0) break;

f=fact(n);
r=fact(k)*fact(n-k);
g=f/r;
printf("%.0Lf\n",g);
}
return 0;
}

### Re: I need Help on 530(Binomial Showdown)

Posted: Sat Oct 03, 2009 8:51 pm
i think there is precision error
So you should use integer operation only

like nCr= n!/(r!* (n-r)!)

n *( n-1)* (n-2)* ...... (n-r+1)* (n-r)* (n-r-1)* ..........3*.2*1
-------------------------------------------------------------------
{r*( r-1)*(r-2).........3.2.1 )} {(n-r)* (n-r-1)...........3*2*1}

n* (n-1)*(n-2)*.............(n-r+1)
---------------------------------------
r*(r-1)*(r-2)*...............3*2*1

let
10 5
so
10*9*8*...............(10-5+1)
-----------------------------------
5 *4*..............2*1

10*9*8*7*6
------------
5*4*3*2*1

= you desired answer

You should use gcd between successive Numerator and denominator

Hopes it helps you

### Re: I need Help on 530(Binomial Showdown)

Posted: Sun Oct 04, 2009 11:55 am
Thank you very much.
I got it.

### Re: I need Help on 530(Binomial Showdown)

Posted: Fri Nov 13, 2009 3:21 pm
what is this ?

### Re: 530 woes

Posted: Mon Feb 01, 2010 10:36 am
my code is below... i dont know why im getting wrong answer... could anyone please help me to find out....???

Code: Select all

``````#include<iostream>
#include<stdio.h>
using namespace std;

int main()
{
long double y,d,k,n;

while((scanf("%lf %lf",&n,&k))==2 && n>=1&& k>=0 && k<=n)
{

d=1;
for( y=0;y<=k-1;y++)
d*=(n-y)/(k-y);

printf("%.lf\n",d);
}
return 0;
}
``````

### 530 Why WA

Posted: Fri Feb 12, 2010 6:42 am
why im getting wrong answer...plz hlp me.... i have got AC in 369 no problem.

Code: Select all

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

int main()
{
long double y,d,k,n;
while((scanf("%lf %lf",&n,&k))==2 && n>=1&& k>=0 && k<=n)
{
d=1;
for( y=0;y<=k-1;y++)
d*=(n-y)/(k-y);
printf("%.lf\n",d);
}
return 0;
}``````

### Re: 530 woes

Posted: Tue Feb 23, 2010 6:53 am
You are using "long double" as data type.
But you are printing :-

Code: Select all

``printf("%.lf\n",d);``
I think this should be changed to:-

Code: Select all

``printf("%.llf\n",d);``
And i think this won't be enough to solve this problem

### Re: 530 woes

Posted: Mon May 31, 2010 6:28 am
can anyone help me please
i am facing time limit error
#include<stdio.h>
double a(int b)
{
int c,e=1;
for(c=1;c<=b;c++)
{
e=e*c;
}
return e;
}

int main()
{
int b,n,r,j=0,d,ans[23];
double e[3];

while(n!=0,r!=0)
{
scanf("%d%d",&n,&r);

if(n==0 && r==0)
break;a
e[0]=a(n);
e[1]=a(r);
e[2]=a(n-r);
ans[j]=e[0]/(e[1]*e[2]);
j++;
}

for(d=0;d<j;d++)
printf("%d\n",ans[d]);
return 0;
}

### Re: 530 woes

Posted: Mon May 31, 2010 12:52 pm
[code#include<stdio.h>
double a(int b)
{
int c,e=1;
for(c=1;c<=b;c++)
{
e=e*c;
}
return e;
}

int main()
{
int b,n,r,j=0,d,ans[23];
double e[3];

while(n!=0,r!=0)
{
scanf("%d%d",&n,&r);

if(n==0 && r==0)
break;a
e[0]=a(n);
e[1]=a(r);
e[2]=a(n-r);
ans[j]=e[0]/(e[1]*e[2]);
j++;
}

for(d=0;d<j;d++)
printf("%d\n",ans[d]);
return 0;
}
]