Cod sursa(job #3123687)

Utilizator Nitoi_BogdanNitoi Andrei-Bogdan Nitoi_Bogdan Data 25 aprilie 2023 09:18:05
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.12 kb
#include <fstream>
#define MOD 666013

using namespace std;

ifstream cin("kfib.in");
ofstream cout("kfib.out");

void copiere(long long a[2][2], long long b[2][2])
{
    for (int i=0; i<=1; i++)
        for (int j=0; j<=1; j++)
            a[i][j] = b[i][j];
}

void inmultire(long long a[2][2], long long b[2][2], long long c[2][2])
{
    int i, j, k;
    for (i=0; i<=1; i++)
        for (j=0; j<=1; j++)
        {
            c[i][j] = 0;
            for (k=0; k<=1; k++)
            {
                c[i][j] += a[i][k] * b[k][j];
                c[i][j] %= MOD;
            }
        }
}

int n;

int main()
{
    cin>>n;
    if (n<=2)
    {
        cout<<1;
        return 0;
    }

    n-=2;
    long long a[2][2] = { {1,1},
        {1,0}
    };

    long long p[2][2] = { {1,0},
        {0,1}
    };

    long long b[2][2];
    while (n)
    {
        if (n%2 == 1)
        {
            inmultire(p, a, b);
            copiere(p, b);
        }
        inmultire(a, a, b);
        copiere(a, b);

        n/=2;

    }
    cout<<(p[0][0] + p[0][1])%MOD;
    return 0;
}