From 4b9258f4c69230f2119c74241bce00b65eed7f02 Mon Sep 17 00:00:00 2001
From: Arek <ar@ar76.eu>
Date: Tue, 11 Feb 2025 22:12:42 +0100
Subject: [PATCH] perf: simpler code in countN

---
 gol/types.go | 22 ++++------------------
 1 file changed, 4 insertions(+), 18 deletions(-)

diff --git a/gol/types.go b/gol/types.go
index fd94667..0c58b08 100644
--- a/gol/types.go
+++ b/gol/types.go
@@ -72,24 +72,10 @@ func (a Arena) countN(x, y int) int {
 	ysize := len(a)
 	xsize := len(a[0])
 
-	xb := x - 1
-	if xb < 0 {
-		xb = xsize - 1
-	}
-	xa := x + 1
-	if xa == xsize {
-		xa = 0
-	}
-
-	yb := y - 1
-	if yb < 0 {
-		yb = ysize - 1
-	}
-
-	ya := y + 1
-	if ya == ysize {
-		ya = 0
-	}
+	xb := (x - 1 + xsize) % xsize
+	xa := (x + 1 + xsize) % xsize
+	yb := (y - 1 + ysize) % ysize
+	ya := (y + 1 + ysize) % ysize
 
 	neigh := [8]pair{
 		{xb, yb},