CalculCombinari

#include<iostream>
#define NMax 1000
using namespace std;
typedef short Huge[NMax+3];

void AtribValue(Huge H,short X) {
  H[0] = 0;
  while (X) {
      ++H[0];
      H[H[0]] = X % 10;
      X /= 10;
  }
}

void Mult(Huge H,short X)
/* H <- H*X */
{short i,T=0;

  for (i=1;i<=H[0];i++)
    { H[i]=H[i]*X+T;
      T=H[i]/10;
      H[i]=H[i]%10;
    }
  while (T) /* Cat timp exista transport */
    { H[++H[0]]=T%10;
      T/=10;
    }
}

void Divide(Huge A,short X)
/* A <- A/X si intoarce A%X */
{ short i,R=0;
  for (i=A[0];i;i--)
    { A[i]=(R=10*R+A[i])/X;
      R%=X;
    }
  while (!A[A[0]] && A[0]>1) A[0]--;
}

void Afisez(Huge H)
{
    for(short i=H[0];i>0;--i)
        cout<<H[i];
    cout<<'\n';
}

void Cnk(unsigned int n,unsigned int k) /// Folosesc coeficientii binomiali
{
    Huge res;
    AtribValue(res,1);
    if(k>n-k) /// C(n, k) = C(n, n-k)
        k=n-k;
    for(unsigned int i=0;i<k;++i) /// Calculez valoarea [n*(n-1)*---*(n-k+1)]/[k*(k-1)*---*1]
    {
        Mult(res,n-i); /// res*=n-i
        Divide(res,i+1); /// res/=(i+1)
    }
    Afisez(res);
}

int main()
{
    int n,k;
    cin>>n>>k;
    Cnk(n,k);
    return 0;
}