package main

func longestConsecutive(nums []int) (length int) {
	n := len(nums)
	if n <= 1 {
		return n
	}
	uf := NewUF(n)
	m := make(map[int]int)
	for i := 0; i < n; i++ {
		if _, ok := m[nums[i]]; !ok {
			m[nums[i]] = i
			if idL, okL := m[nums[i]-1]; okL {
				uf.Union(i, idL)
			}
			if idR, okR := m[nums[i]+1]; okR {
				uf.Union(i, idR)
			}
		}
	}
	for i := 0; i < n; i++ {
		if uf.Size[i] > length {
			length = uf.Size[i]
		}
	}
	return
}

// func main() {
// 	println(longestConsecutive([]int{100, 4, 200, 1, 3, 2}), 4)
// 	println(longestConsecutive([]int{0, -1}), 2)
// }