Given a fibonacci number N, the task is to find the next fibonacci number.
Examples:
Input: N = 5
Output: 8
8 is the next fibonacci number after 5
Input: N = 3
Output: 5
Approach: The ratio of two adjacent numbers in the Fibonacci series rapidly approaches ((1 + sqrt(5)) / 2). So if N is multiplied by ((1 + sqrt(5)) / 2) and round it, the resultant number will be the next fibonacci number.
Below is the implementation of the above approach:
C++
// C++ implementation of the approach #include<bits/stdc++.h> using namespace std;
// Function to return the next // fibonacci number int nextFibonacci( int n)
{ double a = n * (1 + sqrt (5)) / 2.0;
return round(a);
} // Driver code int main()
{ int n = 5;
cout << nextFibonacci(n);
} // This code is contributed by mohit kumar 29 |
Java
// Java implementation of the approach class GFG
{ // Function to return the next
// fibonacci number
static long nextFibonacci( int n)
{
double a = n * ( 1 + Math.sqrt( 5 )) / 2.0 ;
return Math.round(a);
}
// Driver code
public static void main (String[] args)
{
int n = 5 ;
System.out.println(nextFibonacci(n));
}
} // This code is contributed by AnkitRai01 |
Python3
# Python3 implementation of the approach from math import *
# Function to return the next # fibonacci number def nextFibonacci(n):
a = n * ( 1 + sqrt( 5 )) / 2.0
return round (a)
# Driver code n = 5
print (nextFibonacci(n))
|
C#
// C# implementation of the approach using System;
class GFG
{ // Function to return the next
// fibonacci number
static long nextFibonacci( int n)
{
double a = n * (1 + Math.Sqrt(5)) / 2.0;
return ( long )Math.Round(a);
}
// Driver code
public static void Main(String[] args)
{
int n = 5;
Console.WriteLine(nextFibonacci(n));
}
} // This code is contributed by 29AjayKumar |
Javascript
<script> // Javascript implementation of the approach // Function to return the next // fibonacci number function nextFibonacci(n)
{ let a = n * (1 + Math.sqrt(5)) / 2.0;
return Math.round(a);
} // Driver code let n = 5;
document.write(nextFibonacci(n));
// This code is contributed by Mayank Tyagi </script> |
Output:
8
Time Complexity: O(1)
Auxiliary Space: O(1)