fibonacci recursion java
//Using Recursionpublic class FibonacciCalc{ public static int fibonacciRecursion(int n){ if(n == 0){ return 0; } if(n == 1 || n == 2){ return 1; } return fibonacciRecursion(n-2) + fibonacciRecursion(n-1); } public static void main(String args[]) { int maxNumber = 10; System.out.print("Fibonacci Series of "+maxNumber+" numbers: "); for(int i = 0; i < maxNumber; i++){ System.out.print(fibonacciRecursion(i) +" "); } }}
class fibonacci
{
static int fib(int n)
{
int F[][] = new int[][]{{1,1},{1,0}};
if (n == 0)
return 0;
power(F, n-1);
return F[0][0];
}
/* Helper function that multiplies 2 matrices F and M of size 2*2, and
puts the multiplication result back to F[][] */
static void multiply(int F[][], int M[][])
{
int x = F[0][0]*M[0][0] + F[0][1]*M[1][0];
int y = F[0][0]*M[0][1] + F[0][1]*M[1][1];
int z = F[1][0]*M[0][0] + F[1][1]*M[1][0];
int w = F[1][0]*M[0][1] + F[1][1]*M[1][1];
F[0][0] = x;
F[0][1] = y;
F[1][0] = z;
F[1][1] = w;
}
/* Helper function that calculates F[][] raise to the power n and puts the
result in F[][]
Note that this function is designed only for fib() and won't work as general
power function */
static void power(int F[][], int n)
{
int i;
int M[][] = new int[][]{{1,1},{1,0}};
// n - 1 times multiply the matrix to {{1,0},{0,1}}
for (i = 2; i <= n; i++)
multiply(F, M);
}
/* Driver program to test above function */
public static void main (String args[])
{
int n = 9;
System.out.println(fib(n));
}
}
/* This code is contributed by Rajat Mishra */