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  1. #include <iostream>
  2. using namespace std;
  3. void multiply(int F[2][2], int M[2][2]) {
  4.    int a = F[0][0] * M[0][0] + F[0][1] * M[1][0];
  5.    int b= F[0][0] * M[0][1] + F[0][1] * M[1][1];
  6.    int c = F[1][0] * M[0][0] + F[1][1] * M[1][0];
  7.    int d = F[1][0] * M[0][1] + F[1][1] * M[1][1];
  8.    F[0][0] = a;
  9.    F[0][1] = b;
  10.    F[1][0] = c;
  11.    F[1][1] = d;
  12. }
  13. void power(int F[2][2], int n) {
  14.    if (n == 0 || n == 1)
  15.       return;
  16.    int M[2][2] = {{1,1},{1,0}};
  17.    power(F, n / 2);
  18.    multiply(F, F);
  19.    if (n % 2 != 0)
  20.       multiply(F, M);
  21. }
  22. int fibonacci_matrix(int n) {
  23.    int F[2][2] = {{1,1},{1,0}};
  24.    if (n == 0)
  25.       return 0;
  26.    power(F, n - 1);
  27.    return F[0][0];
  28. }
  29. int main() {
  30.    int n;
  31.    cout<<"Enter the number ";
  32.    cin>>n;
  33.    cout<<fibonacci_matrix(n)<<endl;
  34.    return 0;
  35. }
Success #stdin #stdout 0s 15232KB
comments (?)
stdin
stdout 
Enter the number 0
https://ideone.com/5T2k1B
language:
C++ (gcc 8.3)
created:
5 years ago
visibility:
public

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