Cod sursa(job #2450046)

Utilizator PetrescuAlexandru Petrescu Petrescu Data 21 august 2019 17:25:29
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.1 kb
#include <fstream>
#include <cstring>
#define MODULO 666013

using namespace std;

int mat[2][2], sol[2][2];

inline void produs(int a[2][2], int b[2][2], int c[2][2])
{
    int i, j, k;

    for(i = 0; i < 2; i++)
        for(j = 0; j < 2; j++)
            for(k = 0; k < 2; k++)
                c[i][j] = (c[i][j] + 1LL * a[i][k] * b[k][j]) % MODULO;
}

inline void ridicare(int p)
{
    int i, c[2][2], aux[2][2];

    memcpy(c, mat, sizeof(mat));

    for(i = 0; (1 << i) <= p; i++)
    {
        if(p & (1 << i))
        {
            memset(aux, 0, sizeof(aux));
            produs(sol, c, aux);
            memcpy(sol, aux, sizeof(aux));
        }

        memset(aux, 0, sizeof(aux));
        produs(c, c, aux);
        memcpy(c, aux, sizeof(aux));
    }
}

int main()
{
    int n;

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

    fin >> n;

    mat[0][0] = 0;
    mat[0][1] = mat[1][0] = mat[1][1] = 1;

    sol[0][0] = 0;
    sol[0][1] = 1;

    ridicare(n - 1);

    fout << sol[0][1];

    fin.close();
    fout.close();

    return 0;
}