Cod sursa(job #3257100)

Utilizator MikeStrikeAgache Mihai MikeStrike Data 16 noiembrie 2024 17:07:43
Problema Al k-lea termen Fibonacci Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.16 kb
#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

const int MOD = 666013;

void multiplyMatrix(vector<vector<int>> &a, vector<vector<int>> &b) {
    vector<vector<int>> result(2, vector<int>(2));
    for (int i = 0; i < 2; ++i) {
        for (int j = 0; j < 2; ++j) {
            result[i][j] = 0;
            for (int k = 0; k < 2; ++k) {
                result[i][j] = (result[i][j] + 1LL * a[i][k] * b[k][j]) % MOD;
            }
        }
    }
    a = result;
}

void powerMatrix(vector<vector<int>> &matrix, long long n) {
    vector<vector<int>> result = {{1, 0}, {0, 1}};     
       while (n > 0) {
        if (n % 2 == 1) {
            multiplyMatrix(result, matrix);
        }
        multiplyMatrix(matrix, matrix);
        n /= 2;
    }
    matrix = result;
}

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

    long long K;
    fin >> K;

    if (K == 0) {
        fout << 0 << endl;
        return 0;
    }
    if (K == 1) {
        fout << 1 << endl;
        return 0;
    }

    vector<vector<int>> matrix = {{1, 1}, {1, 0}};

    powerMatrix(matrix, K - 1);

    fout << matrix[0][0] << endl;

    return 0;
}