package q4

import "math"

func findMedianSortedArrays(nums1 []int, nums2 []int) float64 {
	l1, l2 := len(nums1), len(nums2)
	even := (l1+l2)%2 == 0

	if l1+l2 == 1 {
		if l1 == 1 {
			return float64(nums1[0])
		}
		return float64(nums2[0])
	}

	// Find how many numbers `nums1` has that are to the left of the median
	nLeft := (len(nums1) + len(nums2)) / 2
	l, r := max(0, nLeft-l2), min(nLeft, len(nums1))+1

Loop:
	for l+1 < r {
		m := (l + r) / 2
		p1 := m - 1
		p2 := nLeft - m - 1

		switch {
		case p2 >= 0 && p1+1 < l1 && nums2[p2] > nums1[p1+1]:
			l = m + 1
		case p1 >= 0 && p2+1 < l2 && nums1[p1] > nums2[p2+1]:
			r = m
		default:
			l = m
			break Loop
		}
	}

	lNum, rNum := math.MinInt, math.MaxInt
	p1 := l - 1
	p2 := nLeft - l - 1
	if p1 >= 0 {
		lNum = max(lNum, nums1[p1])
	}
	if p2 >= 0 {
		lNum = max(lNum, nums2[p2])
	}
	if p1+1 < l1 {
		rNum = min(rNum, nums1[p1+1])
	}
	if p2+1 < l2 {
		rNum = min(rNum, nums2[p2+1])
	}

	if even {
		return float64(lNum+rNum) / 2
	}
	return float64(rNum)
}

var _ = findMedianSortedArrays