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| 1 | +package day4 |
| 2 | + |
| 3 | +import ( |
| 4 | + "bufio" |
| 5 | + "fmt" |
| 6 | + "os" |
| 7 | + "strconv" |
| 8 | + "strings" |
| 9 | +) |
| 10 | + |
| 11 | +func ScratchCards(filepath string) int { |
| 12 | + file, err := os.Open(filepath) |
| 13 | + if err != nil { |
| 14 | + _ = fmt.Errorf("error opening file: %v+", err) |
| 15 | + return 0 |
| 16 | + } |
| 17 | + |
| 18 | + defer func(file *os.File) { |
| 19 | + err := file.Close() |
| 20 | + if err != nil { |
| 21 | + _ = fmt.Errorf("error closing file %v+", err) |
| 22 | + } |
| 23 | + }(file) |
| 24 | + |
| 25 | + scanner := bufio.NewScanner(file) |
| 26 | + totalPoints := 0 |
| 27 | + |
| 28 | + for scanner.Scan() { |
| 29 | + line := scanner.Text() |
| 30 | + parts := strings.Split(line, "|") |
| 31 | + if len(parts) != 2 { |
| 32 | + fmt.Printf("Invalid line format: %s\n", line) |
| 33 | + continue |
| 34 | + } |
| 35 | + |
| 36 | + leftPart := strings.Split(parts[0], ":") |
| 37 | + |
| 38 | + leftNumbers := extractNumbers(leftPart[1]) |
| 39 | + rightNumbers := extractNumbers(parts[1]) |
| 40 | + |
| 41 | + points := calculatePoints(leftNumbers, rightNumbers) |
| 42 | + totalPoints += points |
| 43 | + } |
| 44 | + |
| 45 | + fmt.Printf("Total Points: %d\n", totalPoints) |
| 46 | + return totalPoints |
| 47 | +} |
| 48 | + |
| 49 | +func extractNumbers(s string) []int { |
| 50 | + numStr := strings.Fields(strings.TrimSpace(s)) |
| 51 | + numbers := make([]int, len(numStr)) |
| 52 | + |
| 53 | + for i, str := range numStr { |
| 54 | + num, err := strconv.Atoi(str) |
| 55 | + if err != nil { |
| 56 | + fmt.Printf("Error converting %s to integer: %v\n", str, err) |
| 57 | + continue |
| 58 | + } |
| 59 | + numbers[i] = num |
| 60 | + } |
| 61 | + |
| 62 | + return numbers |
| 63 | +} |
| 64 | + |
| 65 | +func calculatePoints(leftNumbers, rightNumbers []int) int { |
| 66 | + points := 0 |
| 67 | + matched := make(map[int]bool) |
| 68 | + |
| 69 | + for _, num := range rightNumbers { |
| 70 | + if contains(leftNumbers, num) && !matched[num] { |
| 71 | + points++ |
| 72 | + matched[num] = true |
| 73 | + } |
| 74 | + } |
| 75 | + |
| 76 | + if points > 1 { |
| 77 | + points = 2 << (points - 2) |
| 78 | + } |
| 79 | + |
| 80 | + return points |
| 81 | +} |
| 82 | + |
| 83 | +func contains(numbers []int, target int) bool { |
| 84 | + for _, num := range numbers { |
| 85 | + if num == target { |
| 86 | + return true |
| 87 | + } |
| 88 | + } |
| 89 | + return false |
| 90 | +} |
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