Cod sursa(job #2639094)

Utilizator bogdan_modoleaBogdan Modolea bogdan_modolea Data 31 iulie 2020 13:00:55
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.92 kb
#include <bits/stdc++.h>
#define MOD 666013
using namespace std;
typedef long long ll;

string file="kfib";

ifstream fin(file+".in");
ofstream fout(file+".out");

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

void mult2mat(int a[][2], int b[][2]) {
    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;
        }
    }
    for (int i = 0; i < 2; i++)
        for (int j = 0; j < 2; j++)
            a[i][j] = c[i][j];
}

void powermat(int p) {
    while (p > 0) {
        if (p % 2 == 0) {
            mult2mat(A, A);
            p /= 2;
        } else {
            mult2mat(I, A);
            p--;
        }
    }
}

int main()
{
    fin>>k;
    if(k<=1) fout<<k;
    else{
        powermat(k-1);
        fout<<I[0][0];
    }
    return 0;
}