Cod sursa(job #1154546)

Utilizator 0051David Sera 0051 Data 26 martie 2014 11:28:54
Problema Al k-lea termen Fibonacci Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.29 kb
#include <iostream>
#include <fstream>

using namespace std;

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

#define mod 666013

int rez[2][2];

void mul(int ac[2][2], int b[2][2])
{/*
    rez[0][0]=(ac[0][0]*b[0][0])%mod+(ac[0][1]*b[1][0])%mod;
    rez[0][1]=(ac[0][0]*b[0][1])%mod+(ac[0][1]*b[1][1])%mod;
    rez[1][0]=(ac[1][0]*b[0][0])%mod+(ac[1][1]*b[1][0])%mod;
    rez[1][1]=(ac[1][0]*b[0][1])%mod+(ac[1][1]*b[1][1])%mod;
*/
    int i,j,k;
    for(i=0;i<=1;i++)
        for(j=0;j<=1;j++){
            rez[i][j]=0;
            for(k=0;k<=1;k++)
                {
                    rez[i][j]+=(ac[i][k]*b[k][j])%mod;
                    rez[i][j]%=mod;
                }
        }

    ac[0][0]=rez[0][0]%mod;
    ac[0][1]=rez[0][1]%mod;
    ac[1][0]=rez[1][0]%mod;
    ac[1][1]=rez[1][1]%mod;
}

void pow(int aa[2][2], int n)
{
    int p[2][2];
    p[0][0]=1;
    p[0][1]=0;
    p[1][0]=0;
    p[1][1]=1;
    while(n)
    {
        if(n&1)
            mul(p,aa);
        mul(aa,aa);
        n>>=1;
    }
    int i,j;
    for(i=0;i<=1;i++)
        for(j=0;j<=1;j++)
            aa[i][j]=p[i][j];
}

int main()
{
    int a[2][2],n;
    a[0][0]=a[0][1]=a[1][0]=1;
    a[1][1]=0;
    fin>>n;
    pow(a,n-1);
    cout<<a[0][0]<<endl;
    return 0;
}