Day 13

day13/common/distress.go

@@ -0,0 +1,150 @@
+package common
+
+import (
+	"bufio"
+	"strconv"
+)
+
+
+type Packet interface {
+  Compare(Packet) int
+  ToList() ListPacket
+  IsSeparator() bool
+}
+
+
+type IntPacket int
+
+func (packet IntPacket) Compare(other Packet) int {
+  if otherInt, ok := other.(IntPacket); ok {
+    if packet < otherInt {
+      return -1
+    } else if packet > otherInt {
+      return 1
+    } else {
+      return 0
+    }
+  } else {
+    otherList, _ := other.(ListPacket)
+    return packet.ToList().Compare(otherList)
+  }
+}
+
+func (packet IntPacket) ToList() ListPacket {
+  return ListPacket{[]Packet{packet}, false}
+}
+
+func (packet IntPacket) IsSeparator() bool {
+  return false
+}
+
+
+type ListPacket struct {
+  content []Packet
+  separator bool
+}
+
+func (packet ListPacket) Compare(other Packet) int {
+  otherList := other.ToList()
+  comparisonRes := 0
+  for i := 0; comparisonRes == 0; i++ {
+    if i == len(packet.content) && i == len(otherList.content) {
+      break
+    } else if i == len(packet.content) {
+      comparisonRes = -1
+    } else if i == len(otherList.content) {
+      comparisonRes = 1
+    } else {
+      comparisonRes = packet.content[i].Compare(otherList.content[i])
+    }
+  }
+  return comparisonRes
+}
+
+func (packet ListPacket) ToList() ListPacket {
+  return packet
+}
+
+func (packet ListPacket) IsSeparator() bool {
+  return packet.separator
+}
+
+
+type Pair struct {
+  first Packet
+  second Packet
+}
+
+func (pair Pair) CheckOrder() bool {
+  return pair.first.Compare(pair.second) < 0
+}
+
+
+func ParseListPacket(listString string) ListPacket {
+  packet := ListPacket{[]Packet{}, false}
+
+  currI := 1
+  for i := 1; i < len(listString); i++ {
+    if listString[i] == ',' || listString[i] == ']' {
+      if listString[currI] >= '0' && listString[currI] <= '9' {
+        convertedInt, _ := strconv.Atoi(listString[currI:i])
+        packet.content = append(packet.content, IntPacket(convertedInt))
+      } else if listString[currI] == '[' {
+        depth := 1
+        var j int
+        for j = currI + 1; depth != 0; j++ {
+          if listString[j] == '[' {
+            depth++
+          } else if listString[j] == ']' {
+            depth--
+          }
+        }
+        packet.content = append(packet.content, ParseListPacket(listString[currI:j]))
+        i = j
+      }
+      currI = i + 1
+    }
+  }
+
+  return packet
+}
+
+
+func ParsePairs(scanner bufio.Scanner) []Pair {
+  pairs := []Pair{}
+  current := make([]Packet, 0, 2)
+
+  for scanner.Scan() {
+    line := scanner.Text()
+    
+    if line == "" {
+      pairs = append(pairs, Pair{current[0], current[1]})
+      current = make([]Packet, 0, 2)
+    } else {
+      current = append(current, ParseListPacket(line))
+    }
+  }
+
+  return append(pairs, Pair{current[0], current[1]})
+}
+
+
+func ParsePackets(scanner bufio.Scanner, separators []string) []Packet {
+  packets := []Packet{}
+
+  for scanner.Scan() {
+    line := scanner.Text()
+    
+    if line != "" {
+      packets = append(packets, ParseListPacket(line))
+    }
+  }
+
+  for _, separator := range separators {
+    separatorPacket := ParseListPacket(separator)
+    separatorPacket.separator = true
+    packets = append(packets, separatorPacket)
+  }
+
+  return packets
+}

day13/ex1/main.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"aoc2022/day13/common"
+	"bufio"
+	"fmt"
+	"os"
+)
+
+func main() {
+  pairs := common.ParsePairs(*bufio.NewScanner(os.Stdin))
+	sum := 0
+
+	for i, pair := range pairs {
+		if pair.CheckOrder() {
+			sum += (i + 1)
+		}
+	}
+
+  fmt.Println(sum)
+}

day13/ex2/main.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"aoc2022/day13/common"
+	"bufio"
+	"fmt"
+	"os"
+	"sort"
+)
+
+func main() {
+  packets := common.ParsePackets(*bufio.NewScanner(os.Stdin), []string{"[[2]]", "[[6]]"})
+
+	sort.Slice(packets, func(i int, j int) bool {
+		return packets[i].Compare(packets[j]) < 0
+	})
+
+	result := 1
+	for i := 0; i < len(packets); i++ {
+		if packets[i].IsSeparator() {
+			result *= (i+1)
+		}
+	}
+
+  fmt.Println(result)
+}