day4, part2. here come off-by-one errors

day4/dayFour.go

@@ -10,13 +10,57 @@ import (
 func Run() int {
 	fmt.Println("in day 4")
 	cards := ReadAllCards()
-	result := 0
+	fmt.Printf("> got cards %+v\n", cards)
+	// result := 0
 
+	// for _, card := range cards {
+	// 	// fmt.Printf("> checking card %+v with points %d", card, card.GetPoints())
+	// 	result += card.GetPoints()
+	// }
+
+	result := ActuallWinCounting(cards)
+
+	return result
+}
+
+// starting from card #1 count how many winning points it has
+// then add copies to map of 'amount of cards i have'
+// multiplied to amount of current card i have, ok i guess
+func ActuallWinCounting(cards []Card) int {
+	cardAmounts := make(map[int]int)
+	// i had off-by-one error, with card 204 not being updated from 196
+	maxCard := len(cards)
+	fmt.Printf("> counting winning, total cards are %d\ncards are %+v\n\n", maxCard, cards)
 	for _, card := range cards {
-		fmt.Printf("> checking card %+v with points %d", card, card.GetPoints())
-		result += card.GetPoints()
-	}
+		fmt.Printf("> checking card %d\n", card.Title)
+		winningNums := card.GetWinNums()
+		curCardAmount, found := cardAmounts[card.Title]
+		if !found {
+			curCardAmount = 1
+			cardAmounts[card.Title] = curCardAmount
+		}
+		fmt.Printf(">> from curCard %d winning points are %d. And it's amount is %d\n", card.Title, winningNums, curCardAmount)
+		for i := 1; i <= winningNums; i++ {
+			childCardNum := card.Title + i
+			if childCardNum > maxCard {
+				fmt.Printf(">>>> should skip increasing child card %d from curCard %d\n", childCardNum, card.Title)
+				break
+			}
+			curAmount, found := cardAmounts[childCardNum]
+			if !found {
+				cardAmounts[childCardNum] = 1 + curCardAmount
+			} else {
+				cardAmounts[childCardNum] += curCardAmount
+			}
 
+			fmt.Printf(">> increasing child card %d from %d to %d by curCard %d\n", childCardNum, curAmount, cardAmounts[childCardNum], card.Title)
+		}
+	}
+	var result int = 0
+	for _, amount := range cardAmounts {
+		result += amount
+	}
+	fmt.Printf("> got card amounts: %+v\n", cardAmounts)
 	return result
 }
 
@@ -27,14 +71,14 @@ type Card struct {
 }
 
 func ReadAllCards() []Card {
-	filename := "day4/example"
+	filename := "day4/input"
 	bytes, err := os.ReadFile(filename)
 	if err != nil {
 		panic(fmt.Sprintf("can't read file %s", filename))
 	}
 	text := string(bytes)
 	lines := strings.Split(text, "\n")
-	result := make([]Card, len(lines))
+	result := make([]Card, 0, len(lines))
 
 	for _, line := range lines {
 		if line == "" {
@@ -48,12 +92,13 @@ func ReadAllCards() []Card {
 
 // read line like 'Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53'
 func ReadCard(line string) Card {
+	fmt.Printf(">> reading line %s\n", line)
 	result := Card{}
 	extractingTitle := strings.Split(line, ":")
 	title := extractingTitle[0]
 	numberPart := extractingTitle[1]
 
-	titleNumStr := strings.Split(title, " ")[1]
+	titleNumStr := strings.Fields(title)[1]
 	titleNum, err := strconv.Atoi(titleNumStr)
 	if err != nil {
 		panic(fmt.Sprintf("error extracting card title: %s, %s", line, titleNumStr))
@@ -84,6 +129,23 @@ func ReadCard(line string) Card {
 		result.OwnNums = append(result.OwnNums, ownNum)
 	}
 
+	fmt.Printf(">>> returning %+v\n", result)
+	return result
+}
+
+func (c *Card)GetWinNums() int {
+	winningSet := make(map[int]any)
+	for _, winNum := range c.WinningNums {
+		winningSet[winNum] = struct{}{}
+	}
+
+	result := 0
+	for _, ownNum := range c.OwnNums {
+		_, isWinning := winningSet[ownNum]
+		if isWinning {
+			result += 1
+		}
+	}
 	return result
 }