feat: Add samples for calculating the max.

Author: goloroden

README.md

@@ -8,6 +8,7 @@ So far, the following exercises have been covered:
 
 - [Autocomplete](./autocomplete/) – implements an autocomplete feature using a trie
 - [Busfactor](./busfactor/) – calculates the the maximum load of a bus based on events
+- [Clever max](./clevermax/) – calculates the maximum of two numbers
 - [Cons, Car, Cdr & co.](./cons) – implements a cons cell and the corresponding functions
 - [Continous maximum](./continuousmax/) – calculates the maximum of a sliding window
 - [Floyd](./floyd/) – implements Floyd's cycle-finding "Tortoise and Hare" algorithm

clevermax/documentation.go

@@ -0,0 +1,2 @@
+// Package clevermax calculates the maximum of two numbers.
+package clevermax

clevermax/max.go

@@ -0,0 +1,18 @@
+package clevermax
+
+import "math"
+
+func abs(i int) int {
+	return int(math.Sqrt(float64(i * i)))
+}
+
+func Max(left, right int) int {
+	return (left + right + abs(left-right)) / 2
+}
+
+func MaxBitShift(left, right int) int {
+	difference := left - right
+	factor := difference >> 63
+
+	return left + factor*difference
+}

clevermax/max_test.go

@@ -0,0 +1,28 @@
+package clevermax_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/thenativeweb/codingcircle/clevermax"
+)
+
+func TestMax(t *testing.T) {
+	t.Run("returns the larger number as maximum", func(t *testing.T) {
+		assert.Equal(t, 42, clevermax.Max(23, 42))
+	})
+
+	t.Run("returns the given number if both are equal", func(t *testing.T) {
+		assert.Equal(t, 23, clevermax.Max(23, 23))
+	})
+}
+
+func TestMaxBitShift(t *testing.T) {
+	t.Run("returns the larger number as maximum", func(t *testing.T) {
+		assert.Equal(t, 42, clevermax.MaxBitShift(23, 42))
+	})
+
+	t.Run("returns the given number if both are equal", func(t *testing.T) {
+		assert.Equal(t, 23, clevermax.MaxBitShift(23, 23))
+	})
+}