aoc2023/day-4/one.go

package main

import (
	"strings"
	"unicode"
)

// Card represents a single card.
// it tracks its number of matches and occurrences
type Card struct {
	matches     int
	occurrences int
}

var cards = []Card{}

// one computes points based on matching numbers
func one(lines []string) (int, error) {
	f := func(c rune) bool {
		return !unicode.IsDigit(c)
	}

	sum := 0
	cards = make([]Card, len(lines))
	for x, line := range lines {
		winning, mynums := func() (string, string) {
			y := strings.Split(line, ":")
			z := strings.Split(y[1], "|")
			return z[0], z[1]
		}()

		m, err := compare(strings.FieldsFunc(winning, f), strings.FieldsFunc(mynums, f))
		if err != nil {
			return 0, err
		}
		cards[x].matches = m
		if cards[x].matches > 0 {
			sum += (pow(2, cards[x].matches-1))
		}
	}

	return sum, nil
}