20th day

Author: majcn

day20/day20.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	. "majcn.si/advent-of-code-2022/util"
+)
+
+type DataType []int
+
+func parseData(data string) DataType {
+	dataSplit := strings.Split(data, "\n")
+
+	result := make([]int, len(dataSplit))
+	for i, line := range dataSplit {
+		result[i] = ParseInt(line)
+	}
+
+	return result
+}
+
+func solvePartX(data DataType, nrMixes int) (rc int) {
+	myList := NewCircualList(data)
+	myListAsSlice := myList.AsSlice()
+
+	for n := 0; n < nrMixes; n++ {
+		for i := range myListAsSlice {
+			node := myListAsSlice[i]
+			nodeValue := node.Value
+
+			switch {
+			case nodeValue > 0:
+				myNextNode := node.Next
+
+				myList.RemoveNode(node)
+				node = nil
+
+				repeat := (nodeValue % (len(myListAsSlice) - 1)) - 1
+				for c := 0; c < repeat; c++ {
+					myNextNode = myNextNode.Next
+				}
+
+				myListAsSlice[i] = myList.AddAfter(myNextNode, nodeValue)
+			case nodeValue < 0:
+				myPrevNode := node.Prev
+
+				myList.RemoveNode(node)
+				node = nil
+
+				repeat := ((-1 * nodeValue) % (len(myListAsSlice) - 1)) - 1
+				for c := 0; c < repeat; c++ {
+					myPrevNode = myPrevNode.Prev
+				}
+
+				myListAsSlice[i] = myList.AddBefore(myPrevNode, nodeValue)
+			}
+		}
+	}
+
+	node := myList.FindNode(0)
+	for i := 1; i <= 3000; i++ {
+		node = node.Next
+		if i%1000 == 0 {
+			rc += node.Value
+		}
+	}
+
+	return
+}
+
+func solvePart1(data DataType) (rc int) {
+	return solvePartX(data, 1)
+}
+
+func solvePart2(data DataType) (rc int) {
+	modifiedData := make(DataType, len(data))
+	for i, v := range data {
+		modifiedData[i] = v * 811589153
+	}
+
+	return solvePartX(modifiedData, 10)
+}
+
+func main() {
+	data := parseData(FetchInputData(20))
+	fmt.Println(solvePart1(data))
+	fmt.Println(solvePart2(data))
+}

day20/day20_test.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"os"
+	"testing"
+
+	. "majcn.si/advent-of-code-2022/util"
+)
+
+func ExpectedPart1() int {
+	return 3
+}
+
+func ExpectedPart2() int {
+	return 1623178306
+}
+
+var data DataType
+
+func init() {
+	input, _ := os.ReadFile("../examples/20.txt")
+	data = parseData(string(input))
+}
+
+func TestPart1(t *testing.T) {
+	AssertTestPartX(t, ExpectedPart1(), solvePart1(data))
+}
+
+func TestPart2(t *testing.T) {
+	AssertTestPartX(t, ExpectedPart2(), solvePart2(data))
+}

examples/20.txt

@@ -0,0 +1,7 @@
+1
+2
+-3
+3
+-2
+0
+4