feat: Add random arena initialization option and optimize cell life calculation with an early exit.

cmd/gol/gol.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"log"
+	"math/rand"
 	"os"
 	"os/signal"
 	"runtime/pprof"
@@ -15,6 +16,7 @@ import (
 
 func main() {
 	cpuprofile := flag.String("cpuprofile", "", "write cpu profile to file")
+	initrandom := flag.Bool("random", false, "initialize arena with random values")
 	flag.Parse()
 
 	// Jeśli podano flagę cpuprofile, rozpocznij profilowanie
@@ -29,27 +31,39 @@ func main() {
 		}
 		defer pprof.StopCPUProfile()
 	}
-	game()
+	game(*initrandom)
 }
 
-func game() {
+func initArena(front gol.Arena, initRandom bool) {
+	if initRandom {
+		for y := range front {
+			for x := range front[y] {
+				front[y][x] = rand.Intn(2) == 1
+			}
+		}
+	} else {
+		// draw initial objects
+		// glider
+		front[0][3] = true
+		front[1][4] = true
+		front[2][2] = true
+		front[2][3] = true
+		front[2][4] = true
+
+		// cross
+		front[16][21] = true
+		front[17][21] = true
+		front[18][21] = true
+	}
+}
+
+func game(initrandom bool) {
 	// arenas - front one is printed, then new state is calculated into the back one
 	// next front and back are switched
 	front := gol.New(20, 40)
 	back := gol.New(20, 40)
 
-	// draw initial objects
-	// glider
-	front[0][3] = true
-	front[1][4] = true
-	front[2][2] = true
-	front[2][3] = true
-	front[2][4] = true
-
-	// cross
-	front[16][21] = true
-	front[17][21] = true
-	front[18][21] = true
+	initArena(front, initrandom)
 
 	// catch interrupt signals
 	sigs := make(chan os.Signal, 1)

gol/arena.go

@@ -55,12 +55,6 @@ func (a Arena) NextGen(to Arena) {
 }
 
 func (a Arena) life(x, y int) bool {
-	neighbours := a.countNeighbours(x, y)
-	iAmAlive := a[y][x]
-	return neighbours == 3 || (iAmAlive && neighbours == 2)
-}
-
-func (a Arena) countNeighbours(x, y int) int {
 	ysize := len(a)
 	xsize := len(a[0])
 
@@ -75,7 +69,11 @@ func (a Arena) countNeighbours(x, y int) int {
 			if a[ny][nx] {
 				count++
 			}
+			if count > 3 {
+				return false // early exit
+			}
 		}
 	}
-	return count
+	iAmAlive := a[y][x]
+	return count == 3 || (iAmAlive && count == 2)
 }