Cod sursa(job #930988)

Utilizator Stefex09Stefan Teodorescu Stefex09 Data 27 martie 2013 22:16:18
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.2 kb
#include <iostream>
#include <fstream>

using namespace std;

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

const int MOD = 666013;

int Ans[3][3], A[3][3], C[3][3];

inline void Mul (int A[3][3], int B[3][3])
{
    C[1][1] = ((long long) A[1][1] * B[1][1]) % MOD + ((long long) A[1][2] * B[2][1]) % MOD;
    C[1][2] = ((long long) A[1][1] * B[1][2]) % MOD + ((long long) A[1][2] * B[2][2]) % MOD;
    C[2][1] = ((long long) A[2][1] * B[1][1]) % MOD + ((long long) A[2][2] * B[2][1]) % MOD;
    C[2][2] = ((long long) A[2][1] * B[1][2]) % MOD + ((long long) A[2][2] * B[2][2]) % MOD;
    A[1][1] = C[1][1] % MOD;
    A[1][2] = C[1][2] % MOD;
    A[2][1] = C[2][1] % MOD;
    A[2][2] = C[2][2] % MOD;
}

inline int lgpow (int A[3][3], int P)
{
    Ans[1][1] = 1;
    Ans[1][2] = 0;
    Ans[2][1] = 0;
    Ans[2][2] = 1;

    for ( ; P; P >>= 1){
        if (P & 1)
            Mul (Ans, A);

        Mul (A, A);
    }

    return Ans[1][2] % MOD;
}

int main()
{
    int N;
    A[1][1] = 0;
    A[1][2] = 1;
    A[2][1] = 1;
    A[2][2] = 1;

    in >> N;
    if (N < 3){
        out << 1;

        return 0;
    }

    out << lgpow (A, N);

    return 0;
}