Cod sursa(job #3163301)

Utilizator alex_0747Gheorghica Alexandru alex_0747 Data 31 octombrie 2023 11:14:20
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.13 kb
#include <iostream>
#include <fstream>
#define MOD 666013
using namespace std;

ifstream fin("kfib.in");
ofstream fout("kfib.out");

int p[2][2], a[2][2], c[2][2], n;

void Produs(int a[2][2], int b[2][2], int 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] += 1LL * a[i][k] * b[k][j] % MOD;
            c[i][j] %= MOD;
        }
}

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

void Exp(int a[2][2], int n)
{
    p[0][0] = p[1][1] = 1;
    p[0][1] = p[1][0] = 0;
    while (n > 0)
    {
        if (n % 2 == 1)
        {
            Produs(p, a, c);
            Copie(p, c);
        }
        n /= 2;
        Produs(a, a, c);
        Copie(a, c);
    }
}

int main()
{
    a[0][1] = a[1][0] = a[1][1] = 1;
    fin >> n;
    if (n == 0)
    {
        fout << "0\n";
        return 0;
    }
    Exp(a, n - 1);
    fout << p[1][1] << "\n";
    return 0;
}