Cod sursa(job #1891743)

Utilizator dorin31Geman Dorin Andrei dorin31 Data 24 februarie 2017 11:53:48
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.99 kb
#include <iostream>
#include <fstream>

#define mod 666013

using namespace std;

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

int K,res[2][2],cnst[2][2];

void multiply(int a[2][2], int b[2][2]) // a=a*b
{
    int r[2][2];
    for (int i=0; i<2; ++i)
        for (int j=0; j<2; ++j)
        {
            r[i][j]=0;
            for (int p=0; p<2; ++p)
                r[i][j]+=(1LL*a[i][p]*b[p][j])%mod;
        }
    for (int i=0; i<2; ++i)
        for (int j=0; j<2; ++j)
            a[i][j]=r[i][j]%mod;
}

int main()
{
    fin>>K;

    // Init res
    res[1][1]=1; // f0=0, f1=1, f2=1
    // Init const
    cnst[0][0]=0;
    cnst[0][1]=cnst[1][0]=cnst[1][1]=1;

    --K;
    if (K==0) { fout<<0; return 0; }

    while (K)
    {
        if (K%2==1)
        {
            --K;
            multiply(res,cnst);
        }
        else
        {
            K/=2;
            multiply(cnst,cnst);
        }
    }
    fout<<res[1][1];
    return 0;
}