towerofseven_comparison.go

package towerofseven

import (
	"testing"
)

// greatest power of seven within the range of int32
const sevenPowEleven = 1977326743

// returns whether an integer number 'n' == 7**int(x) (a positive integer power of 7)
func TowerOfSevens(n int32) bool {
	/*
		cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
		BenchmarkTowersOfSeven-8   	1000000000	         0.4956 ns/op	       0 B/op	       0 allocs/op
	*/
	return n > 0 && sevenPowEleven%n == 0
}

func TowerOfSevensLoop(n int32) bool {
	/*
		cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
		BenchmarkTowersOfSevenLoop-8   	283085700	         4.334 ns/op	       0 B/op	       0 allocs/op
	*/
	for n%7 == 0 {
		n /= 7
	}
	return n == 1
}

const val0 = 1
const val1 = 7
const val2 = 49
const val3 = 343
const val4 = 2401
const val5 = 16807
const val6 = 117649
const val7 = 823543
const val8 = 5764801
const val9 = 40353607
const val10 = 282475249
const val11 = 1977326743

func TowerOfSevensTable(n int32) bool {
	/*
		cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
		BenchmarkTowersOfSevenTable-8   	1000000000	         0.8043 ns/op	       0 B/op	       0 allocs/op
	*/
	switch n {
	case val0, val1, val2, val3, val4, val5, val6, val7, val8, val9, val10, val11:
		return true
	}
	return false
}

/*
BENCHMARK AND UNIT TESTS
*/

const val = 7*7*7 + 100

func BenchmarkTowersOfSeven(b *testing.B) {
	/*
		goos: windows
		goarch: amd64
		pkg: gitlab.com/yqapp/dev/yq-gateway/appmetrics/towersogseven
		cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
		BenchmarkTowersOfSeven-8   	1000000000	         0.4956 ns/op	       0 B/op	       0 allocs/op
		PASS
		ok  	gitlab.com/yqapp/dev/yq-gateway/appmetrics/towersogseven	1.625s
	*/
	for i := 0; i < b.N; i++ {
		TowerOfSevens(val)
	}
}

func BenchmarkTowersOfSevenLoop(b *testing.B) {
	/*
		goos: windows
		goarch: amd64
		pkg: gitlab.com/yqapp/dev/yq-gateway/appmetrics/towersogseven
		cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
		BenchmarkTowersOfSevenLoop-8   	283085700	         4.334 ns/op	       0 B/op	       0 allocs/op
		PASS
		ok  	gitlab.com/yqapp/dev/yq-gateway/appmetrics/towersogseven	3.699s
	*/
	for i := 0; i < b.N; i++ {
		TowerOfSevensLoop(val)
	}
}

func BenchmarkTowersOfSevenTable(b *testing.B) {
	/*
		goos: windows
		goarch: amd64
		pkg: gitlab.com/yqapp/dev/yq-gateway/appmetrics/towersogseven
		cpu: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz
		BenchmarkTowersOfSevenTable-8   	1000000000	         0.8043 ns/op	       0 B/op	       0 allocs/op
		PASS
		ok  	gitlab.com/yqapp/dev/yq-gateway/appmetrics/towersogseven	1.122s
	*/
	for i := 0; i < b.N; i++ {
		TowerOfSevensTable(val)
	}
}

var poscases = [12]int{
	1,
	7,
	49,
	343,
	2401,
	16807,
	117649,
	823543,
	5764801,
	40353607,
	282475249,
	1977326743,
}

var negcases = [22]int{
	2, 3, 4, 5, 6, 8, 14, 21, 28, 35, 42, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60,
}

func TestTowerOfSevens(t *testing.T) {
	for _, poscase := range poscases {
		if !TowerOfSevens(int32(poscase)) {
			t.Errorf("TowerOfSevens(%d) was 'false' but should be 'true'", poscase)
		}
	}
	for _, negcase := range negcases {
		if TowerOfSevens(int32(negcase)) {
			t.Errorf("TowerOfSevens(%d) was 'true' but should be 'false'", negcase)
		}
	}
}

func TestTowerOfSevensLoop(t *testing.T) {
	for _, poscase := range poscases {
		if !TowerOfSevensLoop(int32(poscase)) {
			t.Errorf("TowerOfSevensLoop(%d) was 'false' but should be 'true'", poscase)
		}
	}
	for _, negcase := range negcases {
		if TowerOfSevensLoop(int32(negcase)) {
			t.Errorf("TowerOfSevensLoop(%d) was 'true' but should be 'false'", negcase)
		}
	}
}

func TestTowerOfSevensTable(t *testing.T) {
	for _, poscase := range poscases {
		if !TowerOfSevensTable(int32(poscase)) {
			t.Errorf("TowerOfSevensTable(%d) was 'false' but should be 'true'", poscase)
		}
	}
	for _, negcase := range negcases {
		if TowerOfSevensTable(int32(negcase)) {
			t.Errorf("TowerOfSevensTable(%d) was 'true' but should be 'false'", negcase)
		}
	}
}