BigFibonacci

#include <iostream>
using namespace std;
#define NMax 10000
typedef int Huge[NMax+3];

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

void CopyHuge(Huge A,Huge B) /// A <- B
{
    for(int i=0;i<=B[0];++i)
        A[i]=B[i];
}

void Add(Huge A, Huge B) /// A <- A+B
{ int i,T=0;

  if (B[0]>A[0])
    { for (i=A[0]+1;i<=B[0];) A[i++]=0;
      A[0]=B[0];
    }
    else for (i=B[0]+1;i<=A[0];) B[i++]=0;
  for (i=1;i<=A[0];i++)
    { A[i]+=B[i]+T;
      T=A[i]/10;
      A[i]%=10;
    }
  if (T) A[++A[0]]=T;
}

void AfisezHuge(Huge A)
{
    for(int i=A[0];i>0;--i)
        cout<<A[i];
}

int main()
{
    int n;
    cin>>n;
    if(n==1||n==2)
    {
        cout<<1;
        return 0;
    }
    Huge F1,F2,F;
    AtribValue(F1,1ULL);
    AtribValue(F2,1ULL);
    for(int i=3;i<=n;++i)
        CopyHuge(F,F1),Add(F,F2),CopyHuge(F1,F2),CopyHuge(F2,F);
    AfisezHuge(F);
    return 0;
}