package longest_consecutive_sequence

// type Node struct {
// 	// The location of the parent node.
// 	Parent *Node

// 	// The number of descendent nodes, including itself.
// 	Children int
// }

// func FindAncestor(n *Node) *Node {
// 	ancestor := n

// 	for ancestor.Parent != nil {
// 		ancestor = ancestor.Parent
// 	}

// 	return ancestor
// }

// func LongestConsecutive(nums []int) int {
// 	nodes := map[int]*Node{}

// 	for _, num := range nums {
// 		if _, exists := nodes[num]; exists {
// 			continue
// 		}

// 		node := &Node{Parent: nil, Children: 1}

// 		if lower, lower_exists := nodes[num-1]; lower_exists {
// 			ancestor := FindAncestor(lower)
// 			ancestor.Parent = node
// 			node.Children += ancestor.Children
// 		}

// 		if upper, lower_exists := nodes[num+1]; lower_exists {
// 			ancestor := FindAncestor(upper)
// 			ancestor.Parent = node
// 			node.Children += ancestor.Children
// 		}

// 		nodes[num] = node
// 	}

// 	maximum := 0

// 	for _, node := range nodes {
// 		maximum = max(maximum, node.Children)
// 	}

// 	return maximum
// }

func LongestConsecutive(nums []int) int {
	items := map[int]bool{}

	for _, num := range nums {
		items[num] = true
	}

	maximum := 0

	for item, unused := range items {
		if !unused {
			continue
		}

		items[item] = false
		sequence := 1

		for i := item - 1; items[i]; i-- {
			items[i] = false
			sequence++
		}

		for i := item + 1; items[i]; i++ {
			items[i] = false
			sequence++
		}

		maximum = max(maximum, sequence)
	}

	return maximum
}