day11

2022/go/day11/day11.go

@@ -0,0 +1,148 @@
+package day11
+
+import (
+	_ "fmt"
+	"strings"
+	"sort"
+	"adventofcode2022/utils"
+	"math/big"
+)
+
+type op int
+
+const (
+	addition op = iota + 1
+	multiply
+	square
+)
+
+type monkey struct {
+	items []*big.Int
+	operation op
+	opArg *big.Int
+	test *big.Int
+	ifTrue int
+	ifFalse int
+	inspected int
+}
+
+func Part1(input string) int {
+
+	monkeys := parseInput(input)
+	var level = big.NewInt(0)
+	for round := 0; round < 20; round++ {
+		for i, monkey := range monkeys {
+			for _, item := range monkey.items {
+				monkeys[i].inspected++
+				switch monkey.operation {
+				case addition:
+					level = new(big.Int).Add(item, monkey.opArg)
+				case multiply:
+					level = new(big.Int).Mul(item, monkey.opArg)
+				case square:
+					level = new(big.Int).Mul(item, item)
+				}
+				level = new(big.Int).Div(level, big.NewInt(3))
+				t := &big.Int{}
+				t.Mod(level, monkey.test)
+				if t.Sign() == 0 {
+					monkeys[monkey.ifTrue].items = append(monkeys[monkey.ifTrue].items, level)
+				} else {
+					monkeys[monkey.ifFalse].items = append(monkeys[monkey.ifFalse].items, level)
+				}
+				
+			}
+			monkeys[i].items = monkeys[i].items[:0]
+		}
+	}
+	sort.Slice(monkeys, func(i, j int) bool {
+		return monkeys[i].inspected > monkeys[j].inspected
+	})
+	
+	return  monkeys[0].inspected * monkeys[1].inspected
+}
+
+func Part2(input string) int {
+	monkeys := parseInput(input)
+	var level = big.NewInt(0)
+	commonDivisor := big.NewInt(3 * 13 * 19 * 17 * 5 * 7 * 11 * 2)
+	for round := 0; round < 10000; round++ {
+		for i, monkey := range monkeys {
+			for _, item := range monkey.items {
+				monkeys[i].inspected++
+				switch monkey.operation {
+				case addition:
+					level = new(big.Int).Add(item, monkey.opArg)
+				case multiply:
+					level = new(big.Int).Mul(item, monkey.opArg)
+				case square:
+					level = new(big.Int).Mul(item, item)
+				}
+				level = level.Mod(level, commonDivisor)
+				t := &big.Int{}
+				t.Mod(level, monkey.test)
+				if t.Sign() == 0 {
+					monkeys[monkey.ifTrue].items = append(monkeys[monkey.ifTrue].items, level)
+				} else {
+					monkeys[monkey.ifFalse].items = append(monkeys[monkey.ifFalse].items, level)
+				}
+				
+			}
+			monkeys[i].items = monkeys[i].items[:0]
+		}
+	}
+	sort.Slice(monkeys, func(i, j int) bool {
+		return monkeys[i].inspected > monkeys[j].inspected
+	})
+	
+	return  monkeys[0].inspected * monkeys[1].inspected
+}
+
+func parseInput(input string) []monkey {
+	monkeys := []monkey{}
+
+	for i, monkeyString := range strings.Split(input, "\n\n") {
+		for _, line := range strings.Split(monkeyString, "\n") {
+			if strings.HasPrefix(line, "Monkey") {
+				monkeys = append(monkeys, monkey{})
+			} else if strings.HasPrefix(line, "  Starting items: ") {
+				s := strings.TrimPrefix(line, "  Starting items: ")
+				for _, piece := range strings.Split(s, ", ") {
+					t := utils.MustAtoi(piece)
+					monkeys[i].items =  append(monkeys[i].items, big.NewInt(int64(t)))
+				}
+			} else if strings.HasPrefix(line, "  Operation: new = ") {
+				s := strings.TrimPrefix(line, "  Operation: new = ")
+				if strings.HasPrefix(s, "old + ") {
+					s2 := strings.TrimPrefix(s, "old + ")
+					monkeys[i].operation = addition
+					t := utils.MustAtoi(s2)
+					monkeys[i].opArg = big.NewInt(int64(t))
+				} else if s == "old * old" {
+					monkeys[i].operation = square
+				} else if strings.HasPrefix(s, "old * ") {
+					s2 := strings.TrimPrefix(s, "old * ")
+					monkeys[i].operation = multiply
+					t := utils.MustAtoi(s2)
+					monkeys[i].opArg = big.NewInt(int64(t))
+				}
+
+			} else if strings.HasPrefix(line, "  Test: divisible by ") {
+				s := strings.TrimPrefix(line, "  Test: divisible by ")
+				t := utils.MustAtoi(s)
+				monkeys[i].test = big.NewInt(int64(t))
+			} else if strings.HasPrefix(line, "    If true: throw to monkey ") {
+				s := strings.TrimPrefix(line, "    If true: throw to monkey ")
+				monkeys[i].ifTrue = utils.MustAtoi(s)
+			} else if strings.HasPrefix(line, "    If false: throw to monkey ") {
+				s := strings.TrimPrefix(line, "    If false: throw to monkey ")
+				monkeys[i].ifFalse = utils.MustAtoi(s)
+			} else if line == "" {
+				// do nothing
+			} else {
+				panic("unknown input")
+			}
+		}
+	}
+	return monkeys
+}

2022/go/day11/day11_test.go

@@ -0,0 +1,45 @@
+package day11
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestPart1(t *testing.T) {
+	r := Part1(
+`Monkey 0:
+Starting items: 79, 98
+Operation: new = old * 19
+Test: divisible by 23
+  If true: throw to monkey 2
+  If false: throw to monkey 3
+
+Monkey 1:
+Starting items: 54, 65, 75, 74
+Operation: new = old + 6
+Test: divisible by 19
+  If true: throw to monkey 2
+  If false: throw to monkey 0
+
+Monkey 2:
+Starting items: 79, 60, 97
+Operation: new = old * old
+Test: divisible by 13
+  If true: throw to monkey 1
+  If false: throw to monkey 3
+
+Monkey 3:
+Starting items: 74
+Operation: new = old + 3
+Test: divisible by 17
+  If true: throw to monkey 0
+  If false: throw to monkey 1
+`)
+	require.Equal(t, 10605, r)
+}
+
+func TestPart2(t *testing.T) {
+	r := Part2("")
+	require.Equal(t, 0, r)
+}

2022/go/day11/input.txt

@@ -0,0 +1,55 @@
+Monkey 0:
+  Starting items: 54, 98, 50, 94, 69, 62, 53, 85
+  Operation: new = old * 13
+  Test: divisible by 3
+    If true: throw to monkey 2
+    If false: throw to monkey 1
+
+Monkey 1:
+  Starting items: 71, 55, 82
+  Operation: new = old + 2
+  Test: divisible by 13
+    If true: throw to monkey 7
+    If false: throw to monkey 2
+
+Monkey 2:
+  Starting items: 77, 73, 86, 72, 87
+  Operation: new = old + 8
+  Test: divisible by 19
+    If true: throw to monkey 4
+    If false: throw to monkey 7
+
+Monkey 3:
+  Starting items: 97, 91
+  Operation: new = old + 1
+  Test: divisible by 17
+    If true: throw to monkey 6
+    If false: throw to monkey 5
+
+Monkey 4:
+  Starting items: 78, 97, 51, 85, 66, 63, 62
+  Operation: new = old * 17
+  Test: divisible by 5
+    If true: throw to monkey 6
+    If false: throw to monkey 3
+
+Monkey 5:
+  Starting items: 88
+  Operation: new = old + 3
+  Test: divisible by 7
+    If true: throw to monkey 1
+    If false: throw to monkey 0
+
+Monkey 6:
+  Starting items: 87, 57, 63, 86, 87, 53
+  Operation: new = old * old
+  Test: divisible by 11
+    If true: throw to monkey 5
+    If false: throw to monkey 0
+
+Monkey 7:
+  Starting items: 73, 59, 82, 65
+  Operation: new = old + 6
+  Test: divisible by 2
+    If true: throw to monkey 4
+    If false: throw to monkey 3

2022/go/main.go

@@ -18,6 +18,8 @@ import (
 	"adventofcode2022/day08"
 	"adventofcode2022/day09"
 	"adventofcode2022/day10"
+	"adventofcode2022/day11"
+
 
 )
 
@@ -58,6 +60,9 @@ func main() {
 	case 10:
 		fmt.Printf("part 1: %d\n", day10.Part1(utils.Readfile(d)))
 		fmt.Printf("part 2: %s\n", day10.Part2(utils.Readfile(d)))
+	case 11:
+		fmt.Printf("part 1: %d\n", day11.Part1(utils.Readfile(d)))
+		fmt.Printf("part 2: %d\n", day11.Part2(utils.Readfile(d)))
 	default:
 		panic(fmt.Errorf("no such day: %d", d))
 	}
@@ -65,7 +70,7 @@ func main() {
 
 // Reads day from os.Args.
 func day() int {
-	latest := 9
+	latest := 10
 	if len(os.Args) == 1 {
 		return latest
 	}