Cod sursa(job #3188615)

Utilizator robert_dumitruDumitru Robert Ionut robert_dumitru Data 3 ianuarie 2024 15:33:49
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.25 kb
#include <bits/stdc++.h>
using namespace std;
#define MOD 666013

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

int n;
long long a[2][2], b[2][2], c[2][2];

void Inmultire(long long a[2][2], long long b[2][2], long long c[2][2])
{
    c[0][0] = (a[0][0] * b[0][0] + a[0][1] * b[1][0]) % MOD;
    c[0][1] = (a[0][0] * b[0][1] + a[0][1] * b[1][1]) % MOD;
    c[1][0] = (a[1][0] * b[0][0] + a[1][1] * b[1][0]) % MOD;
    c[1][1] = (a[1][0] * b[0][1] + a[1][1] * b[1][1]) % MOD;
}

void LogExpo(int p)
{
    while (p >= 1)
    {
        if (p % 2 == 1)
        {
            Inmultire(a, b, c);
            for (int i = 0; i < 2; i++)
                for (int j = 0; j < 2; j++)
                    a[i][j] = c[i][j];
        }
        p /= 2;
        Inmultire(b, b, c);
        for (int i = 0; i < 2; i++)
                for (int j = 0; j < 2; j++)
                    b[i][j] = c[i][j];
    }
}

int main()
{
    fin >> n;
    a[0][0] = 1; b[0][0] = 0;
    a[0][1] = 0; b[0][1] = 1;
    a[1][0] = 0; b[1][0] = 1;
    a[1][1] = 1; b[1][1] = 1;
    ///a retine matricea z la n - 1
    LogExpo(n - 1);

    b[0][0] = 0;
    b[0][1] = 1;
    b[1][0] = 0;
    b[1][1] = 0;
    Inmultire(b, a, c);
    fout << c[0][1] << "\n";
}