From 2d2a5e7bd6ec8428119efdca41fa0e53c465a071 Mon Sep 17 00:00:00 2001
From: Karl Spickermann <karliosos65@googlemail.com>
Date: Fri, 3 Dec 2021 23:16:30 +0100
Subject: [PATCH] Move copy of array in filterNumbersPart2

---
 src/day3/day3.go | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/day3/day3.go b/src/day3/day3.go
index 76b0c53..b2f6259 100644
--- a/src/day3/day3.go
+++ b/src/day3/day3.go
@@ -27,8 +27,8 @@ func main() {
 }
 
 func part2(intArray [][]int) {
-	oxygenGeneratorRating, _ := filterNumbersPart2(append([][]int(nil), intArray...), 0)
-	co2ScrubberRating, _ := filterNumbersPart2(append([][]int(nil), intArray...), 1)
+	oxygenGeneratorRating, _ := filterNumbersPart2(intArray, 0)
+	co2ScrubberRating, _ := filterNumbersPart2(intArray, 1)
 	fmt.Println(co2ScrubberRating * oxygenGeneratorRating)
 }
 
@@ -42,21 +42,23 @@ func part1(intArray [][]int) {
 }
 
 func filterNumbersPart2(intArray [][]int, invert int) (int64, error){
-	gammaArray := getGammaArray(intArray, invert)
+	intArrayCopy := make([][]int, len(intArray))
+	copy(intArrayCopy, intArray)
+	gammaArray := getGammaArray(intArrayCopy, invert)
 	i := 0
-	for len(intArray) > 1 {
+	for len(intArrayCopy) > 1 {
 		n := 0
-		for _, number := range intArray {
+		for _, number := range intArrayCopy {
 			if number[i] == gammaArray[i] {
-				intArray[n] = number
+				intArrayCopy[n] = number
 				n++
 			}
 		}
-		intArray = intArray[:n]
-		gammaArray = getGammaArray(intArray, invert)
+		intArrayCopy = intArrayCopy[:n]
+		gammaArray = getGammaArray(intArrayCopy, invert)
 		i++
 	}
-	s, _ := json.Marshal(intArray[0])
+	s, _ := json.Marshal(intArrayCopy[0])
 	intString := strings.Replace(strings.Trim(string(s), "[]"),",","",-1)
 	return strconv.ParseInt(intString, 2, 64)
 }