Day 5

day05/common/crane.go

@@ -0,0 +1,85 @@
+package common
+
+import (
+	"bufio"
+	"strconv"
+	"strings"
+)
+
+type Stack []byte
+
+func (stack *Stack) Append(crate byte) {
+  *stack = append(Stack{crate}, *stack...)
+}
+
+func (stack *Stack) Push(crate byte) {
+  *stack = append(*stack, crate)
+}
+
+func (stack *Stack) Pop() byte {
+  last := len(*stack) - 1
+  top := (*stack)[last]
+  *stack = (*stack)[:last]
+  return top
+}
+
+func (stack *Stack) Peek() byte {
+  last := len(*stack) - 1
+  top := (*stack)[last]
+  return top
+}
+
+type Movement struct {
+  n int
+  start int
+  end int
+}
+
+func (movement Movement) GetN() int {
+  return movement.n
+}
+
+func (movement Movement) GetStart() int {
+  return movement.start
+}
+
+func (movement Movement) GetEnd() int {
+  return movement.end
+}
+
+func Parse(scanner bufio.Scanner) ([]Stack, []Movement) {
+  stacks := []Stack{}
+
+  scanner.Scan()
+  line := scanner.Text()
+
+  nStacks := len(line) / 4 + 1
+
+  for i := 0; i < nStacks; i++ {
+    stacks = append(stacks, Stack{})
+  }
+
+  for line[:3] != " 1 " {
+    for i := 0; i < nStacks; i++ {
+      if line[1+4*i] != ' ' {
+        stacks[i].Append(line[1+4*i])
+      }
+    }
+    scanner.Scan()
+    line = scanner.Text()
+  }
+
+  scanner.Scan()
+
+  movements := []Movement{}
+
+  for scanner.Scan() {
+    splittedLine := strings.Split(scanner.Text(), " ")
+    n, _ := strconv.Atoi(splittedLine[1])
+    start, _ := strconv.Atoi(splittedLine[3])
+    end, _ := strconv.Atoi(splittedLine[5])
+    movements = append(movements, Movement{n, start, end})
+  }
+
+  return stacks, movements
+}

day05/ex1/main.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+  "bufio"
+  "fmt"
+  "os"
+  "aoc2022/day05/common"
+)
+
+func main() {
+  stacks, movements := common.Parse(*bufio.NewScanner(os.Stdin))
+
+  for _, movement := range(movements) {
+    for i := 0; i < movement.GetN(); i++ {
+      top := stacks[movement.GetStart() - 1].Pop()
+      stacks[movement.GetEnd() - 1].Push(top)
+    }
+  }
+
+  for _, stack := range(stacks) {
+    fmt.Print(string(stack.Peek()))
+  }
+  fmt.Println()
+}

day05/ex2/main.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+  "bufio"
+  "fmt"
+  "os"
+  "aoc2022/day05/common"
+)
+
+func main() {
+  stacks, movements := common.Parse(*bufio.NewScanner(os.Stdin))
+
+  for _, movement := range(movements) {
+    top := []byte{}
+    for i := 0; i < movement.GetN(); i++ {
+      top = append(top, stacks[movement.GetStart() - 1].Pop())
+    }
+    for i := len(top) - 1; i >= 0; i-- {
+      stacks[movement.GetEnd() - 1].Push(top[i])
+    }
+  }
+
+  for _, stack := range(stacks) {
+    fmt.Print(string(stack.Peek()))
+  }
+  fmt.Println()
+}