fibonacci.mjs

   1 import { bench, group, run } from 'tatami-ng'
   2
   3 const number = 30
   4
   5 /**
   6  * @param num
   7  * @returns
   8  */
   9 function fibonacciLoop (num) {
  10   const fib = []
  11   fib[0] = 0
  12   fib[1] = 1
  13   for (let i = 2; i <= num; i++) {
  14     fib[i] = fib[i - 2] + fib[i - 1]
  15   }
  16   return fib[num]
  17 }
  18
  19 /**
  20  *
  21  * @param num
  22  * @returns
  23  */
  24 function fibonacciLoopWhile (num) {
  25   let current = 1
  26   let previous = 0
  27   while (--num) {
  28     const tmp = current
  29     current += previous
  30     previous = tmp
  31   }
  32   return current
  33 }
  34
  35 /**
  36  * @param num
  37  * @returns
  38  */
  39 function fibonacciRecursion (num) {
  40   if (num <= 1) return num
  41   return fibonacciRecursion(num - 1) + fibonacciRecursion(num - 2)
  42 }
  43
  44 /**
  45  * @param num
  46  * @param memo
  47  * @returns
  48  */
  49 function fibonacciRecursionMemoization (num, memo) {
  50   memo = memo || {}
  51
  52   if (memo[num]) return memo[num]
  53   if (num <= 1) return num
  54
  55   return (memo[num] =
  56     fibonacciRecursionMemoization(num - 1, memo) +
  57     fibonacciRecursionMemoization(num - 2, memo))
  58 }
  59
  60 group(`Fibonacci number ${number}`, () => {
  61   bench('fibonacciLoop', () => {
  62     fibonacciLoop(number)
  63   })
  64   bench('fibonacciLoopWhile', () => {
  65     fibonacciLoopWhile(number)
  66   })
  67   bench('fibonacciRecursion', () => {
  68     fibonacciRecursion(number)
  69   })
  70   bench('fibonacciRecursionMemoization', () => {
  71     fibonacciRecursionMemoization(number)
  72   })
  73 })
  74
  75 await run({
  76   units: true
  77 })