package main

import "fmt"

func average(nums []float64) float64 {
	if len(nums) == 0 {
		return 0
	}
	var sum float64
	for _, i := range nums {
		sum += i
	}
	return sum / float64(len(nums))
}

func filter(nums []float64, comp func(float64, float64) bool) []float64 {
	if len(nums) == 0 {
		return make([]float64, 0)
	}
	val, idxVal := nums[0], 0
	for idx, num := range nums {
		if comp(num, val) {
			val, idxVal = num, idx
		}
	}
	nums = append(nums[:idxVal], nums[idxVal+1:]...)
	return nums
}

func centeredAverage(nums ...float64) float64 {
	nums = filter(nums, func(a float64, b float64) bool {
		return a > b
	})
	nums = filter(nums, func(a float64, b float64) bool {
		return a < b
	})
	return average(nums)
}

func main() {
	fmt.Println(centeredAverage())
	fmt.Println(centeredAverage(1, 2, 3, 4, 100))
	fmt.Println(centeredAverage(1))
	fmt.Println(centeredAverage(1, 1))
	fmt.Println(centeredAverage(1, 1, 1))
}