day 07 part 2

07/main.go

@@ -2,13 +2,29 @@ package main
 
 import (
 	"fmt"
+	"strings"
 
 	"git.z1glr.de/advent-of-code-2025/pkg/aoc"
 )
 
 type Schematic struct {
-	rows   [][]byte
-	splits int
+	rows      []string
+	timelines [][]int
+	splits    int
+}
+
+func (s *Schematic) Calculate() {
+	startIndex := strings.Index(s.rows[0], "S")
+
+	s.timelines = make([][]int, len(s.rows))
+
+	for ii, rr := range s.rows {
+		s.timelines[ii] = make([]int, len(rr))
+	}
+
+	s.timelines[0][startIndex] = 1
+
+	s.CalculateRow(0)
 }
 
 func (s *Schematic) CalculateRow(i int) {
@@ -16,91 +32,39 @@ func (s *Schematic) CalculateRow(i int) {
 		return
 	}
 
-	for ii, char := range s.rows[i] {
-		switch char {
-		case byte('S'), byte('|'):
-			s.processPosition(i+1, ii)
+	for ii, count := range s.timelines[i] {
+		switch s.rows[i+1][ii] {
+		case byte('^'):
+			s.timelines[i+1][ii-1] += count
+			s.timelines[i+1][ii+1] += count
+
+			if s.timelines[i][ii] > 0 {
+				s.splits++
+			}
+		default:
+			s.timelines[i+1][ii] += count
 		}
 	}
 
 	s.CalculateRow(i + 1)
 }
 
-func (s *Schematic) processPosition(row, index int) {
-	if s.rows[row][index] == byte('.') {
-		s.rows[row][index] = byte('|')
-	} else if s.rows[row][index] == byte('^') {
-		s.splits++
-
-		s.rows[row][index-1] = byte('|')
-		s.rows[row][index+1] = byte('|')
-	}
-}
-
-func (s *Schematic) Clone() *Schematic {
-	returnSchematic := Schematic{
-		rows:   make([][]byte, len(s.rows)),
-		splits: s.splits,
-	}
-
-	for ii, rr := range s.rows {
-		returnSchematic.rows[ii] = make([]byte, len(rr))
-		copy(returnSchematic.rows[ii], s.rows[ii])
-	}
-
-	return &returnSchematic
-}
-
-func (s Schematic) CalculateQuantumRow(i int, pathCount *int) {
-	if i == len(s.rows)-1 {
-		return
-	}
-
-	for ii, char := range s.rows[i] {
-		switch char {
-		case byte('S'), byte('|'):
-			if s.rows[i+1][ii] == byte('^') {
-				(*pathCount)++
-
-				parallelPath := s.Clone()
-
-				s.rows[i+1][ii-1] = byte('|')
-				parallelPath.rows[i+1][ii+1] = byte('|')
-
-				parallelPath.CalculateQuantumRow(i+1, pathCount)
-			} else {
-				s.rows[i+1][ii] = byte('|')
-			}
-			s.CalculateQuantumRow(i+1, pathCount)
-			return
-		}
-	}
-	s.CalculateQuantumRow(i+1, pathCount)
-}
-
 func do(test bool) (int, int) {
-	rows := aoc.ReadFileRows(test)
-
 	schematic := Schematic{
-		rows: make([][]byte, len(rows)),
+		rows: aoc.ReadFileRows(test),
 	}
 
-	for ii, rr := range rows {
-		schematic.rows[ii] = []byte(rr)
+	schematic.Calculate()
+
+	timelineCount := 0
+	for _, cc := range schematic.timelines[len(schematic.timelines)-1] {
+		timelineCount += cc
 	}
 
-	quantumSchematic := schematic.Clone()
-
-	schematic.CalculateRow(0)
-
-	timelines := 1
-
-	quantumSchematic.CalculateQuantumRow(0, &timelines)
-
 	fmt.Println(schematic.splits)
-	fmt.Println(timelines)
+	fmt.Println(timelineCount)
 
-	return schematic.splits, timelines
+	return schematic.splits, timelineCount
 }
 
 func main() {