day18, example second parallel

day18/lagoon.go

@@ -7,12 +7,13 @@ import (
 	"slices"
 	"strconv"
 	"strings"
+	"sync"
 )
 
 func Run() int {
 	log.Println("hello day 18")
 	log.Println("problem of lagoon bgins")
-	filename := "day18/example"
+	filename := "day18/input"
 	instructions := ReadInstructionas2(filename)
 	h, w := calcHeightWidth(instructions)
 	log.Printf("read %+v instructions", instructions)
@@ -210,8 +211,10 @@ type Cell struct {
 }
 
 type BorderSymbol rune
-// '' always left to right
+
-const (Vertical BorderSymbol = '|'
+// ” always left to right
+const (
+	Vertical BorderSymbol = '|'
 	ToDown   BorderSymbol = '7'
 	ToUp     BorderSymbol = 'J'
 	FromUp   BorderSymbol = 'F'
@@ -225,19 +228,20 @@ type Field struct {
 	MinRow, MaxRow, MinCol, MaxCol int
 	BordersFromLeft                map[int]map[int]BorderSymbol
 }
-func (f *Field)confirmCoord(c Coord) {
+
+func (f *Field) confirmCoord(c Coord) {
 	// log.Printf("configming coord %+v", c)
 
-	if c.Row - 3 < f.MinRow {
+	if c.Row-3 < f.MinRow {
 		f.MinRow = c.Row - 3
 	}
-	if c.Row + 3 > f.MaxRow {
+	if c.Row+3 > f.MaxRow {
 		f.MaxRow = c.Row + 3
 	}
-	if c.Col - 3 < f.MinCol {
+	if c.Col-3 < f.MinCol {
 		f.MinCol = c.Col - 3
 	}
-	if c.Col + 3 > f.MaxCol {
+	if c.Col+3 > f.MaxCol {
 		f.MaxCol = c.Col + 3
 	}
 }
@@ -337,7 +341,6 @@ func getTurnAsIfGoingFromLeft(directionFrom, directionTo Direction)  []BorderSym
 		symbol = FromUp
 	}
 
-
 	// panic(fmt.Sprint("got strange from %s to %s", directionFrom.String(), directionTo.String()))
 	return []BorderSymbol{symbol}
 }
@@ -346,27 +349,27 @@ func (f *Field) String() string {
 	s := "text 15,15 \""
 
 	for row := f.MinRow; row <= f.MaxRow; row++ {
-		rowChars := make([]rune, f.MaxCol - f.MinCol + 1)
+		rowChars := make([]rune, f.MaxCol-f.MinCol+1)
 		for col := f.MinCol; col <= f.MaxCol; col++ {
 
 			rowBords := f.BordersFromLeft[row]
 			if rowBords != nil {
 				bord, exists := rowBords[col]
 				if exists {
-					rowChars[col - f.MinCol] = rune(bord)
+					rowChars[col-f.MinCol] = rune(bord)
 					continue
 				}
 			}
 			cell := f.Cells[Coord{col, row}]
 			if cell != nil && cell.ToBeDug {
-				rowChars[col - f.MinCol] = '@'
+				rowChars[col-f.MinCol] = '@'
 				continue
 			}
 
 			if f.isCellDug(row, col) {
-				rowChars[col - f.MinCol] = '#'
+				rowChars[col-f.MinCol] = '#'
 			} else {
-				rowChars[col - f.MinCol] = '.'
+				rowChars[col-f.MinCol] = '.'
 			}
 		}
 
@@ -376,14 +379,36 @@ func (f *Field) String() string {
 	s += "\""
 	return s
 }
-func (f *Field) digInsides() (countInside int) {
+func (f *Field) digInsides() (result int) {
+	lineSum := make(chan int)
+
+	var wg sync.WaitGroup
+	rowsCount := f.MaxRow - f.MinRow
+	wg.Add(rowsCount)
+
+	done := make(chan bool)
+
+	go func() {
+		wg.Wait()
+		close(lineSum)
+	}()
+
+	go func() {
+		for rowInternalCount := range lineSum {
+			result += rowInternalCount
+		}
+		close(done)
+	}()
+
 	for row := f.MinRow; row < f.MaxRow; row++ {
-		if row % 10000 == 0 {
+		go func(row int){
+			if row%10000 == 0 {
 				log.Printf("processed rows %d out of %d", row, f.MaxRow)
 			}
 			specialBorders := f.BordersFromLeft[row]
 			if len(specialBorders) == 0 {
-			continue
+				wg.Done()
+				return
 			}
 			type BorderItem struct {
 				border BorderSymbol
@@ -425,13 +450,14 @@ func (f *Field) digInsides() (countInside int) {
 					continue
 				}
 
-			if bordersCrossed % 2 == 1 { // is in
+				if bordersCrossed%2 == 1 { // is in
-				for col := prevBorder.col+1; col < specialBorder.col; col++ {
+					for col := prevBorder.col + 1; col < specialBorder.col; col++ {
 						// f.Cells[Coord{Col: col, Row: row}] = &Cell{
 						// 	ToBeDug: true,
 						// }
 					}
-				countInside += diff
+					lineSum <- diff
+					// countInside += diff
 				}
 
 				if specialBorder.border == Vertical {
@@ -440,8 +466,14 @@ func (f *Field) digInsides() (countInside int) {
 
 				prevBorder = specialBorder
 			}
+
+			wg.Done()
+		}(row)
 	}
-	return
+
+	<-done
+
+	return result
 }
 
 // func (f *Field) digInsides() (countInside int) {

day18/notes.org

@@ -34,3 +34,18 @@ day18 result: 952408144115
 
 952408144115
 *** YES.
+*** about 1M for 4 minutes
+** so, my input is ~16M rows
+3.5 seconds per 10k
+** well, maybe i can parallel.
+*** parallel example
+day18 result: 952407566854
+*** and with separate done channel from the summing goroutine
+952408144115
+**** YES
+** and
+2023/12/18 23:35:31 border is 195341588; inside is 148441957805559
+2023/12/18 23:35:31
+
+day18 result: 148442153147147
+* i should have used a formula. maybe then it would taken less than 4 hours