package medianofarrays

import (
	"math"
	"sort"
)

func median(xs []int) float64 {
	half := float64(len(xs)) / 2
	if len(xs)%2 == 0 {
		return float64(xs[int(half)]+xs[int(half-1)]) / 2
	}

	return float64(xs[int(half)])
}

func sever(xs []int) (head int, tail []int) {
	if len(xs) > 0 {
		return xs[0], xs[1:]
	}
	return math.MaxInt, xs
}

func findMedianSortedArrays(nums1 []int, nums2 []int) float64 {
	if len(nums1) == 0 && len(nums2) == 0 {
		return math.NaN()
	}
	combined := make([]int, len(nums1)+len(nums2))

	for i := range combined {
		lhead, ltail := sever(nums1)
		rhead, rtail := sever(nums2)

		if lhead < rhead {
			combined[i] = lhead
			nums1 = ltail
		} else {
			combined[i] = rhead
			nums2 = rtail
		}
	}

	return median(combined)
}

func FindMedianSortedArrays(nums1 []int, nums2 []int) float64 {
	return findMedianSortedArrays(nums1, nums2)

}

func Lazy(nums1 []int, nums2 []int) float64 {
	combined := append(nums1, nums2...)
	sort.Ints(combined)
	return median(combined)
}