package main

import (
	"bufio"
	"io"
	"log"
	"os"
	"strings"
)

type Group struct {
	QuestionsAnsweredWithYes []rune
	Persons                  []string
}

func (g *Group) SumOfAgreedQuestions() int {
	sum := 0
	for _, answer := range g.QuestionsAnsweredWithYes {
		allAnsweredWithYes := true
		for _, person := range g.Persons {
			personHasAnsweredWithYes := false
			for _, personAnswer := range person {
				if personAnswer == answer {
					personHasAnsweredWithYes = true
					break
				}
			}
			if !personHasAnsweredWithYes {
				allAnsweredWithYes = false
				break
			}
		}
		if allAnsweredWithYes {
			sum++
		}
	}
	return sum
}

func FromLines(lines []string) *Group {
	g := &Group{
		QuestionsAnsweredWithYes: []rune{},
		Persons:                  []string{},
	}
	for _, line := range lines {
		g.Persons = append(g.Persons, line)
	thisPersonsAnswer:
		for _, answer := range line {
			for _, alreadyAnswered := range g.QuestionsAnsweredWithYes {
				if alreadyAnswered == answer {
					continue thisPersonsAnswer
				}
			}
			g.QuestionsAnsweredWithYes = append(g.QuestionsAnsweredWithYes, answer)
		}
	}
	return g
}

func main() {
	groups := []*Group{}

	f, err := os.Open("input")
	if err != nil {
		panic(err)
	}
	r := bufio.NewReader(f)
	currentGroup := []string{}
	for {
		line, err := r.ReadString('\n')
		line = strings.TrimSpace(line)
		if err == io.EOF || len(line) <= 0 {
			if len(currentGroup) > 0 {
				groups = append(groups, FromLines(currentGroup))
				currentGroup = []string{}
			}
			if err == io.EOF {
				break
			}
			continue
		}
		if err != nil {
			panic(err)
		}
		currentGroup = append(currentGroup, line)
	}

	sum := 0
	for _, group := range groups {
		sum += group.SumOfAgreedQuestions()
	}

	log.Printf("Sum: %d", sum)
}