package main

import (
	"fmt"
	"sort"
)

func main() {
	fmt.Println(longestConsecutive([]int{0}))
}

func longestConsecutive(nums []int) int {
	exist := make(map[int]struct{})
	hash := make(map[int]int)
	maxresult := 0
	sort.Slice(nums, func(i, j int) bool {
		return nums[i] < nums[j]
	})
	for i := 0; i < len(nums); i++ {
		exist[nums[i]] = struct{}{}
	}
	for i := 0; i < len(nums); i++ {
		j := nums[i]
		v := 0
		for {
			j++
			if _, ok := exist[j]; ok {
				v += 1
				if _, okk := exist[j+1]; okk {
					delete(exist, j)
				}
			} else {
				break
			}
		}
		hash[nums[i]] = v + 1
		if v >= maxresult {
			maxresult = v + 1
		}
	}
	return maxresult
}