find_num_near_fibonacci.rb

## Task 1
# find closest border number in fib sequence
# near_fib_number(9) => 8
# near_fib_number(12) => 13
require 'benchmark'

def near_fib_number(num)
  start_array = [0, 1]

  while !(start_array[0] <= num && start_array[1] >= num) do
    start_array[2] = start_array[0] + start_array[1]
    start_array.shift
  end

  left_diff = (num - start_array[0]).abs
  puts "left_diff: #{left_diff}"
  right_diff = (num - start_array[1]).abs
  puts "right_diff: #{right_diff}"

  if left_diff < right_diff
    puts start_array[0]
  else
    puts start_array[1]
  end
end

near_fib_number(8)
#=>
# left_diff: 3
# right_diff: 0
# 8
near_fib_number(9)
# left_diff: 1
# right_diff: 4
# 8
near_fib_number(12)
# left_diff: 4
# right_diff: 1
# 13
near_fib_number(14)
# left_diff: 1
# right_diff: 7
# 13
near_fib_number(20)
# left_diff: 7
# right_diff: 1
# 21

Benchmark.bm do |x|
#   user     system      total        real
  x.report {near_fib_number(12)} 
# 0.000009   0.000005   0.000014 (  0.000011)
  x.report {near_fib_number(2_000_000)}
# 0.000005   0.000003   0.000008 (  0.000007)
  x.report {near_fib_number(200_000_000)}
# 0.000006   0.000002   0.000008 (  0.000008)
end