Sum of numbers in the Kth level of a Fibonacci triangle | Java implementation to find the Sum of numbers in the Kth level of a Fibonacci triangle ; Function to return the nth Fibonacci number ; Function to return the required sum of the array ; Using our deduced result ; Function to return the sum of fibonacci in the Kth array ; Count of fibonacci which are in the arrays from 1 to k - 1 ; Driver code
import java . util . * ; class GFG { static int fib ( int n ) { double phi = ( 1 + Math . sqrt ( 5 ) ) / 2 ; return ( int ) Math . round ( Math . pow ( phi , n ) / Math . sqrt ( 5 ) ) ; } static int calculateSum ( int l , int r ) { int sum = fib ( r + 2 ) - fib ( l + 1 ) ; return sum ; } static int sumFibonacci ( int k ) { int l = ( k * ( k - 1 ) ) / 2 ; int r = l + k ; int sum = calculateSum ( l , r - 1 ) ; return sum ; } public static void main ( String args [ ] ) { int k = 3 ; System . out . println ( sumFibonacci ( k ) ) ; } }