code.go 1.2 KB

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  1. package main
  2. import (
  3. "bufio"
  4. "fmt"
  5. "log"
  6. "os"
  7. )
  8. type rucksack struct {
  9. first map[byte]int
  10. second map[byte]int
  11. }
  12. func readInput(file *os.File) []rucksack {
  13. scanner := bufio.NewScanner(file)
  14. var rucksacks []rucksack
  15. for scanner.Scan() {
  16. line := scanner.Text()
  17. if line == "" {
  18. continue
  19. }
  20. edge := len(line)
  21. half := edge / 2
  22. start := 0
  23. current := rucksack{make(map[byte]int), make(map[byte]int)}
  24. for {
  25. if half >= edge {
  26. break
  27. }
  28. current.first[line[start]]++
  29. current.second[line[half]]++
  30. start++
  31. half++
  32. }
  33. rucksacks = append(rucksacks, current)
  34. }
  35. return rucksacks
  36. }
  37. func getPriority(item byte) int {
  38. if item < 96 {
  39. return int(item) - 38
  40. }
  41. return int(item) - 96
  42. }
  43. func part1(rucksacks []rucksack) int {
  44. sum := 0
  45. for i := range rucksacks {
  46. for key, _ := range rucksacks[i].first {
  47. if rucksacks[i].second[key] > 0 {
  48. sum += getPriority(key)
  49. }
  50. }
  51. }
  52. return sum
  53. }
  54. func main() {
  55. if len(os.Args) < 2 {
  56. log.Fatal("You need to specify a file!")
  57. }
  58. filePath := os.Args[1]
  59. file, err := os.Open(filePath)
  60. if err != nil {
  61. log.Fatalf("Failed to open %s!\n", filePath)
  62. }
  63. rucksacks := readInput(file)
  64. fmt.Println("Part1:", part1(rucksacks))
  65. }