Cod sursa(job #2674177)

Utilizator raduk11Serban Mihai-Radu raduk11 Data 18 noiembrie 2020 18:38:27
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.34 kb
#include <iostream>
#include <fstream>
using namespace std;
const int mod=666013,p=1332028;//perioada modulo mod

ifstream f("kfib.in");
ofstream g("kfib.out");

int fibonacci(int n)
{
    if(n==0) return 0;
    int f0=0,f1=1,f2;
    for(int i=2;i<=n;i++)
    {
        f2=(f0+f1)%mod;
        f0=f1;
        f1=f2;
    }
    return f1;
}
int main()
{
    int k;
    f>>k;
    g<<fibonacci(k%p);
    return 0;
}


///varianta 2 - calcul matriceal

/*
#include <fstream>
#include <cstring>
using namespace std;
const int mod=666013;

int a[2][2]= {{1,1},{1,0}},
i[2][2]= {{1,0},{0,1}};

ifstream f("kfib.in");
ofstream g("kfib.out");
void multmat(int a[][2],int b[][2])
{
    int c[2][2];
    for(int i=0; i<2; i++)
        for(int j=0; j<2; j++)
        {
            c[i][j]=0;
            for(int k=0; k<2; k++)
                c[i][j]=(c[i][j]+1ll*a[i][k]*b[k][j])%mod;
        }
        memcpy(a,c,sizeof(c));///copiem pe c in a
}
void puteremat(int p) ///logaritmic
{
    while(p>0)
        if(p%2==0)
        {
            multmat(a,a);
            p/=2;
        }
        else
        {
            multmat(i,a);
            p--;
        }
}
int main()
{
    int k;
    f>>k;
    if(k<=1)
        g<<k;
    else
    {
        puteremat(k-1);
        g<<i[0][0];
    }
    return 0;
}
*/