Cod sursa(job #3314156)

Utilizator popescumalinaPopescu Malina popescumalina Data 8 octombrie 2025 19:03:27
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.93 kb
#include <iostream>
#include <fstream>

using namespace std;
const int MOD = 666013;

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

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

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

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];
    }
    f.close();
    g.close();
    return 0;
}