Cod sursa(job #727643)

Utilizator AndreiRSStatescu Andrei Rares AndreiRS Data 28 martie 2012 10:11:26
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 0.89 kb
#include <fstream>
using namespace std;

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

const int MOD = 666013;
int K, M[3][3] = {{0,0,0},{0,0,1},{0,1,1}}, B[3][3] = {{0,0,0},{0,0,1},{0,1,1}};

void mulmat (int A[3][3], int B[3][3])
{
	long long C[3][3];
	for (int i = 1; i <= 2; i++)
		for (int j = 1; j <= 2; j++)
			C[i][j] = 0;	
	for (int i = 1; i <= 2; i++)
	{
		for (int j = 1; j <= 2; j++)
		{
			for (int k = 1; k <= 2; k++)
			{
				C[i][j] += (long long) A[i][k] * B[k][j];				
			}
			C[i][j] %= MOD;
		}
	}
	for (int i = 1; i <= 2; i++)
		for (int j = 1; j <= 2; j++)
			A[i][j] = C[i][j];
}

void explog (int e)
{
	if (e == 1) return;
	explog (e / 2);
	mulmat (M, M);
	if (e & 1) mulmat (M, B);
}

int main ()
{
	fi >> K;
	if (K < 2)
		fo << K;
	else
	{
		explog (K - 2);
		fo << (M[2][1] + M[2][2]) % MOD;
	}
	fo << '\n';
	return 0;
}