Cod sursa(job #1796647)

Utilizator BlackNestaAndrei Manaila BlackNesta Data 3 noiembrie 2016 17:32:26
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.2 kb
#include <bits/stdc++.h>
#define mod 666013

using namespace std;

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

int N;
int a[3][3], b[3][3];

inline void Copy(int a[3][3], int b[3][3])
{
    for(int i = 1; i <= 2; i++)
        for(int j = 1; j <= 2; j++)
            a[i][j] = b[i][j];
}

inline void Mat_Mult(int a[3][3], int b[3][3])
{
    int c[3][3];
    int i, j, k;
    long long s;
    for(i = 1; i <= 2; i++)
        for(j = 1; j <= 2; j++)
        {
            s = 0;
            for(k = 1; k <= 2; k++)
                s += (1LL* a[i][k] * b[k][j]);
            c[i][j] = s%mod;
        }
    Copy(a, c);
}

inline void Pow_Log(int a[3][3],int p)
{
    int c[3][3];
    c[1][1] = 0;
    c[1][2] = c[2][1] = c[2][2] = 1;
    while(p)
    {
        if(p % 2 == 1)
        {
            Mat_Mult(c, a);
            p--;
        }
        Mat_Mult(a, a);
        p /= 2;
    }
    Copy(a, c);
}


int main()
{
    f >> N;
    a[1][2] = 1;
    b[1][2] = b[2][1] = b[2][2] = 1;
    if(N == 0) g << "0\n";
    else
    {
        Pow_Log(b, N-1);
        Mat_Mult(a, b);
        g << a[1][1] << "\n";
    }
    f.close();
    g.close();
    return 0;
}