Cod sursa(job #2638606)

Utilizator chriss_b_001Cristian Benghe chriss_b_001 Data 29 iulie 2020 08:58:48
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.02 kb
#include <fstream>
#include <cstring>

using namespace std;
const int MOD = 666013;

int A[2][2] = {{1, 1}, {1, 0}},
I[2][2] = {{1, 0}, {0, 1}};

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

void multmat(int a[][2], int b[][2])///a <-- a*b
{
    int c[2][2];
    for(int i = 0; i < 2; i++)
        for(int j = 0; j < 2; j++)
        {
            c[i][j] = 0;
            for(int k = 0; k < 2; k++)
                c[i][j] = (c[i][j] + 1LL * a[i][k] * b[k][j]) % MOD;
        }
    memcpy(a, c, sizeof(c)); /// a <-- c
//    for(int i = 0; i < 2; i++)
//        for(int j = 0; j < 2; j++)
//            a[i][j] = c[i][j];
}

void puteremat(int p)
{
    while(p > 0)
        if(p % 2 == 0)
        {
            multmat(A, A);
            p /= 2;
        }
        else
        {
            multmat(I, A);
            p--;
        }
}

int main()
{
    int k;
    f >> k;
    if(k <= 1)
        g << k;
    else
    {
        puteremat(k - 1);
        g << I[0][0];
    }
    return 0;
}