LeetCode/go/find-the-minimum-and-maximum-number-of-nodes-between-critical-points.go

package main

func nodesBetweenCriticalPoints(head *ListNode) []int {
	OUT_OF_BOUNDS_DISTANCE := 1000000

	isCritical := func(x, y, z int) bool {
		return (y < x && y < z) || (y > x && y > z)
	}

	minDistance := OUT_OF_BOUNDS_DISTANCE

	previous, node := head, head.Next
	previousIdx, firstIdx := 0, 0

	index := 1
	for node.Next != nil {
		if isCritical(previous.Val, node.Val, node.Next.Val) {
			if previousIdx == 0 {
				firstIdx = index
			} else {
				minDistance = min(minDistance, index-previousIdx)
			}

			previousIdx = index
		}

		index++
		previous, node = node, node.Next
	}

	if minDistance != OUT_OF_BOUNDS_DISTANCE {
		return []int{minDistance, previousIdx - firstIdx}
	}

	return []int{-1, -1}
}