Find maximum element of slice in the specified range

find_maximum.go

package main

import "fmt"

func main() {
	a := []int{5, 3, 3, 4, 5}
	fmt.Println(findMaximum(a, 0, 4))
}

func findMaximum(A []int, left, right int) int {
	mid := (left + right) / 2
	if left == right-1 {
		return A[left]
	}
	u := findMaximum(A, left, mid)
	v := findMaximum(A, mid, right)
	return max(u, v)
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

find_maximum_test.go

package main

import (
	"reflect"
	"testing"
)

var findMaximumTests = []struct {
	name  string
	a     []int
	left  int
	right int
	want  int
}{
	{
		name:  "should return maximum value from full range of slice",
		a:     []int{5, 3, 2, 10, 14, 20},
		left:  0,
		right: 6,
		want:  20,
	},
	{
		name:  "should return maximum value from adjacent elements of slice",
		a:     []int{5, 3, 2, 10, 14, 20},
		left:  1,
		right: 2,
		want:  3,
	},
}

func TestFindMaximum(t *testing.T) {
	for _, testcase := range findMaximumTests {
		t.Log(testcase.name)

		if result := findMaximum(testcase.a, testcase.left, testcase.right); !reflect.DeepEqual(result, testcase.want) {
			t.Errorf("result => %#v\n, want => %#v", result, testcase.want)
		}
	}
}