Benchmarking solutions for https://www.codewars.com/kata/53da3dbb4a5168369a0000fe

even_or_odd_test.go

package even_or_odd

import (
	"testing"
	"math"
)

type Solution func (int) string

var smartMap = map[int]string{0: "Even", 1: "Odd"}
var smartSlice = [...]string{"Even","Odd"}
const even = "Even"
const odd = "Odd"

func Naive(i int) string {
	if i % 2 == 0 {
		return "Even"
	}
	return "Odd"
}

func NaiveConst(i int) string {
	if i % 2 == 0 {
		return even
	}
	return odd
}

func NaiveExtraVar(i int) string {
	if j := i % 2; j == 0 {
		return "Even"
	}
	return "Odd"
}

func SemiSmartMapConst(i int) string {
	if i % 2 == 0 {
		return smartMap[0]
	}
	return smartMap[1]
}

func SemiSmartSliceConst(i int) string {
	if i % 2 == 0 {
		return smartSlice[0]
	}
	return smartSlice[1]
}


func Math(i int) string {
	if j := math.Mod(float64(i), 2.0); j == 0 {
		return "Even"
	}
	return "Odd"
}

func MathConst(i int) string {
	if j := math.Mod(float64(i), 2.0); j == 0 {
		return even
	}
	return odd
}

func SmartMap(i int) string {
	return map[int]string{0:"Even", 1:"Odd"}[i % 2]
}

func SmartSlice(i int) string {
	return [...]string{"Even","Odd"}[i % 2]
}

func SmartMapConst(i int) string {
	return smartMap[i % 2]
}

func SmartSliceConst(i int) string {
	return smartSlice[i % 2]
}

func benchmark(b *testing.B, s Solution) {
	for n := 0; n < b.N;  n++ {
		for i := 0; i < 1000000; i++ {
			s(i);
		}
	}
}

func BenchmarkNaive(b *testing.B) {
	benchmark(b, Naive)
}

func BenchmarkNaiveConst(b *testing.B) {
	benchmark(b, NaiveConst)
}

func BenchmarkNaiveExtraVar(b *testing.B) {
	benchmark(b, NaiveExtraVar)
}

func BenchmarkSemiSmartMap(b *testing.B) {
	benchmark(b, SemiSmartMapConst)
}

func BenchmarkSemiSmartSlice(b *testing.B) {
	benchmark(b, SemiSmartSliceConst)
}

func BenchmarkMath(b *testing.B) {
	benchmark(b, Math)
}

func BenchmarkMathConst(b *testing.B) {
	benchmark(b, MathConst)
}

func BenchmarkSmartMap(b *testing.B) {
	benchmark(b, SmartMap)
}

func BenchmarkSmartSlice(b *testing.B) {
	benchmark(b, SmartSlice)
}

func BenchmarkSmartMapConst(b *testing.B) {
	benchmark(b, SmartMapConst)
}

func BenchmarkSmartSliceConst(b *testing.B) {
	benchmark(b, SmartSliceConst)
}

//
// Results:
//
// BenchmarkNaive-4             	     500	   3947839 ns/op
// BenchmarkNaiveConst-4        	     500	   3732272 ns/op
// BenchmarkNaiveExtraVar-4     	     500	   3894234 ns/op
// BenchmarkSemiSmartMap-4      	     100	  11112005 ns/op
// BenchmarkSemiSmartSlice-4    	     500	   3865519 ns/op
// BenchmarkMath-4              	       5	 292276168 ns/op
// BenchmarkMathConst-4         	       5	 288597383 ns/op
// BenchmarkSmartMap-4          	       3	 382927711 ns/op
// BenchmarkSmartSlice-4        	     300	   4245053 ns/op
// BenchmarkSmartMapConst-4     	     100	  11165296 ns/op
// BenchmarkSmartSliceConst-4   	     300	   4232659 ns/op
// PASS
// ok  	indiesoft/codewarriors/even_or_odd	22.490s
//