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> |
8
Time Complexity: O(1)
Auxiliary Space: O(1)
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