gistfile1.txt

package main

import (
	"fmt"
	"sort"

	advent "github.com/mdempsky/advent2020"
)

func main() {
	joltages := advent.InputInts()
	sort.Ints(joltages)

	var distinct [3]int

	joltage := 0
	distinct[joltage] = 1

	for len(joltages) > 0 {
		joltage++

		x := 0
		if joltage == joltages[0] {
			joltages = joltages[1:]
			x = distinct[0] + distinct[1] + distinct[2]
		}
		distinct[joltage%3] = x
	}

	fmt.Println(distinct[joltage%3])
}