Cod sursa(job #1909315)

Utilizator CraiuAndrei Craiu Craiu Data 7 martie 2017 12:18:35
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.25 kb
#include <bits/stdc++.h>

using namespace std;

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

const int MOD = 666013;
int n;
int a[5][5], b[5][5];

inline void Copy(int a[][5], int b[][5])
{
    int i, j;
    for(i = 1; i <= 2; i++)
        for(j = 1; j <= 2; j++)
            a[i][j] = b[i][j];
}

inline void Mult_Mat(int a[][5], int b[][5])
{
    int c[5][5], i, j, k;
    for(i = 0; i <= 4; i++)
        for(j = 0; j <= 4; j++)
            c[i][j] = 0;
    for(i = 1; i <= 2; i++)
        for(k = 1; k <= 2; k++)
            for(j = 1; j <= 2; j++)
                c[i][j] = (c[i][j] + 1LL * a[i][k] * b[k][j]) % MOD;
    Copy(a, c);
}

inline void Lg_Pow(int a[][5], int p)
{
    int c[5][5], i, j;
    for(i = 0; i <= 4; i++)
        for(j = 0; j <= 4; j++)
            c[i][j] = 0;
    c[1][1] = c[2][2] = 1;
    while(p)
    {
        if(p & 1)
            Mult_Mat(c, a);
        p >>= 1;
        Mult_Mat(a, a);
    }
    Copy(a, c);
}

inline void Solve()
{
    a[1][2] = 1;
    b[1][2] = b[2][1] = b[2][2]=1;
    Lg_Pow(b, n - 1);
    Mult_Mat(a, b);
    fout << a[1][2] << "\n";
}

int main()
{
    fin >> n;
    if(!n) fout << "0\n";
    else Solve();
    fin.close();fout.close();
    return 0;
}