Completed day 5 of 2022 in go

2022/go/05/answer.go

@@ -0,0 +1,152 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type Stack []byte
+
+func (s *Stack) String() string {
+	var res strings.Builder
+
+	for _, crate := range *s {
+		res.WriteByte(crate)
+		res.WriteString(" ")
+	}
+	return res.String()
+}
+
+func (s *Stack) isEmpty() bool {
+	return len(*s) == 0
+}
+
+func (s *Stack) push(t ...byte) {
+	*s = append(*s, t...)
+}
+
+func (s *Stack) pop(n int) ([]byte, error) {
+	if s.isEmpty() {
+		return nil, errors.New("Couldn't pop from empty stack")
+	}
+	index := len(*s) - n
+	ret := (*s)[index:]
+	*s = (*s)[:index]
+	return ret, nil
+}
+
+type Move struct {
+	n, from, to int
+}
+
+type Input struct {
+	stacks []Stack
+	moves  []Move
+}
+
+func input(filename string) *Input {
+	file, err := os.Open(filename)
+	check(err, "Couldn't open %q", filename)
+	defer file.Close()
+
+	input := &Input{}
+
+	scanner := bufio.NewScanner(file)
+
+	scanner.Split(bufio.ScanLines)
+
+	var n_stacks int = 0
+
+	// Parse the stacks
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		if line[1] == '1' {
+			break
+		}
+
+		if len(input.stacks) == 0 {
+			n_stacks = (len(line) + 1) / 4
+			input.stacks = make([]Stack, n_stacks)
+		}
+
+		for i := 0; i < n_stacks; i++ {
+			crate := line[4*i+1]
+			if crate != ' ' {
+				input.stacks[i].push(crate)
+			}
+		}
+	}
+
+	// Reverse the stacks since they were added top-down and not bottom-up
+	for _, stack := range input.stacks {
+		for i, j := 0, len(stack)-1; i < j; i, j = i+1, j-1 {
+			stack[i], stack[j] = stack[j], stack[i]
+		}
+	}
+
+	scanner.Scan() // get rid of the empty line after the labeling of the stacks
+
+	// Parse the moves
+	for scanner.Scan() {
+		line := scanner.Text()
+		tokens := strings.Split(line, " ")
+
+		n, err := strconv.Atoi(tokens[1])
+		check(err, "Couldn't convert %q to int", tokens[1])
+		from, err := strconv.Atoi(tokens[3])
+		check(err, "Couldn't convert %q to int", tokens[3])
+		to, err := strconv.Atoi(tokens[5])
+		check(err, "Couldn't convert %q to int", tokens[5])
+
+		input.moves = append(input.moves, Move{
+			n:    n,
+			from: from,
+			to:   to,
+		})
+	}
+
+	return input
+}
+
+func result(inp *Input, part int8) string {
+	var res strings.Builder
+
+	for _, move := range inp.moves {
+		moving, err := inp.stacks[move.from-1].pop(int(move.n))
+		check(err, "ntm")
+		if part == 1 {
+			for i, j := 0, len(moving)-1; i < j; i, j = i+1, j-1 {
+				moving[i], moving[j] = moving[j], moving[i]
+			}
+		}
+
+		inp.stacks[move.to-1].push(moving...)
+	}
+
+	for _, stack := range inp.stacks {
+		log.Print(stack.String())
+		res.WriteByte(stack[len(stack)-1])
+	}
+
+	return res.String()
+}
+
+func check(e error, msg string, vals ...any) {
+	if e != nil {
+		log.Printf("ERROR: "+msg, vals)
+		panic(e)
+	}
+}
+
+func main() {
+	result := result(input("sample1"), 1)
+
+	log.Println(result)
+	fmt.Println(result)
+}

2022/go/05/answer_test.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestInputSample1(t *testing.T) {
+	filename := "sample1"
+	expected := &Input{
+		stacks: []Stack{
+			{'Z', 'N'},
+			{'M', 'C', 'D'},
+			{'P'},
+		},
+		moves: []Move{
+			{1, 2, 1},
+			{3, 1, 3},
+			{2, 2, 1},
+			{1, 1, 2},
+		},
+	}
+	var got *Input = input(filename)
+
+	if !reflect.DeepEqual(expected, got) {
+		t.Errorf("input(%q) = %v, want %v", filename, got, expected)
+	}
+}
+
+func TestResult(t *testing.T) {
+	tests := []struct {
+		part     int8
+		filename string
+		expected string
+	}{
+		{1, "sample1", "CMZ"},
+		{1, "input", "TDCHVHJTG"},
+
+		{2, "sample1", "MCD"},
+		{2, "input", "NGCMPJLHV"},
+	}
+
+	for _, test := range tests {
+		var got string = result(input(test.filename), test.part)
+
+		if got != test.expected {
+			t.Errorf("result = %q, want %q", got, test.expected)
+		}
+	}
+}

2022/go/05/go.mod

@@ -0,0 +1,3 @@
+module aoc/5
+
+go 1.20

2022/go/05/input

@@ -0,0 +1,512 @@
+[F]         [L]     [M]            
+[T]     [H] [V] [G] [V]            
+[N]     [T] [D] [R] [N]     [D]    
+[Z]     [B] [C] [P] [B] [R] [Z]    
+[M]     [J] [N] [M] [F] [M] [V] [H]
+[G] [J] [L] [J] [S] [C] [G] [M] [F]
+[H] [W] [V] [P] [W] [H] [H] [N] [N]
+[J] [V] [G] [B] [F] [G] [D] [H] [G]
+ 1   2   3   4   5   6   7   8   9 
+
+move 6 from 4 to 3
+move 5 from 8 to 9
+move 1 from 4 to 5
+move 1 from 4 to 5
+move 2 from 2 to 7
+move 2 from 1 to 6
+move 9 from 6 to 1
+move 12 from 3 to 5
+move 1 from 8 to 4
+move 3 from 1 to 5
+move 1 from 6 to 7
+move 10 from 5 to 2
+move 14 from 5 to 1
+move 8 from 7 to 9
+move 11 from 2 to 9
+move 1 from 3 to 9
+move 11 from 1 to 5
+move 2 from 1 to 9
+move 1 from 4 to 8
+move 6 from 1 to 5
+move 1 from 8 to 3
+move 16 from 5 to 1
+move 4 from 1 to 3
+move 1 from 5 to 6
+move 4 from 3 to 4
+move 1 from 6 to 7
+move 21 from 9 to 6
+move 2 from 1 to 9
+move 2 from 4 to 9
+move 5 from 9 to 4
+move 9 from 1 to 6
+move 6 from 4 to 6
+move 1 from 6 to 2
+move 1 from 7 to 6
+move 1 from 3 to 2
+move 8 from 6 to 9
+move 3 from 1 to 8
+move 1 from 2 to 1
+move 13 from 6 to 3
+move 1 from 1 to 9
+move 2 from 1 to 6
+move 3 from 8 to 4
+move 4 from 4 to 9
+move 3 from 1 to 3
+move 22 from 9 to 8
+move 1 from 2 to 9
+move 6 from 8 to 9
+move 15 from 6 to 5
+move 5 from 8 to 9
+move 11 from 9 to 8
+move 13 from 5 to 1
+move 1 from 6 to 5
+move 1 from 9 to 3
+move 21 from 8 to 3
+move 3 from 5 to 3
+move 11 from 1 to 2
+move 25 from 3 to 1
+move 5 from 1 to 7
+move 20 from 1 to 7
+move 1 from 6 to 7
+move 16 from 3 to 9
+move 8 from 9 to 6
+move 1 from 1 to 5
+move 5 from 9 to 4
+move 2 from 2 to 1
+move 2 from 9 to 4
+move 1 from 9 to 4
+move 1 from 8 to 4
+move 1 from 5 to 2
+move 3 from 4 to 6
+move 1 from 4 to 7
+move 9 from 7 to 6
+move 5 from 4 to 6
+move 7 from 7 to 2
+move 1 from 1 to 6
+move 11 from 2 to 5
+move 10 from 5 to 1
+move 1 from 6 to 8
+move 1 from 5 to 7
+move 24 from 6 to 1
+move 12 from 1 to 4
+move 12 from 4 to 8
+move 2 from 2 to 7
+move 3 from 7 to 2
+move 5 from 2 to 8
+move 9 from 8 to 9
+move 9 from 8 to 5
+move 1 from 9 to 1
+move 14 from 1 to 8
+move 11 from 7 to 9
+move 4 from 1 to 3
+move 7 from 1 to 2
+move 3 from 3 to 7
+move 12 from 9 to 7
+move 8 from 7 to 2
+move 4 from 9 to 2
+move 1 from 3 to 6
+move 5 from 5 to 9
+move 14 from 2 to 1
+move 8 from 9 to 4
+move 6 from 4 to 5
+move 5 from 5 to 7
+move 1 from 8 to 2
+move 2 from 4 to 6
+move 4 from 7 to 3
+move 10 from 8 to 4
+move 2 from 3 to 6
+move 7 from 7 to 6
+move 10 from 4 to 8
+move 5 from 1 to 6
+move 8 from 2 to 1
+move 7 from 6 to 8
+move 9 from 6 to 5
+move 16 from 1 to 6
+move 2 from 3 to 9
+move 1 from 7 to 4
+move 2 from 9 to 1
+move 14 from 6 to 7
+move 1 from 6 to 3
+move 2 from 6 to 3
+move 9 from 5 to 7
+move 3 from 1 to 6
+move 3 from 3 to 7
+move 5 from 5 to 9
+move 3 from 6 to 2
+move 1 from 6 to 2
+move 12 from 8 to 2
+move 5 from 2 to 1
+move 2 from 1 to 3
+move 25 from 7 to 1
+move 1 from 4 to 6
+move 2 from 3 to 9
+move 26 from 1 to 9
+move 2 from 1 to 8
+move 1 from 6 to 8
+move 1 from 7 to 1
+move 7 from 8 to 1
+move 7 from 1 to 5
+move 1 from 1 to 2
+move 2 from 8 to 6
+move 32 from 9 to 8
+move 1 from 6 to 5
+move 5 from 2 to 9
+move 1 from 9 to 7
+move 24 from 8 to 3
+move 1 from 6 to 9
+move 3 from 2 to 5
+move 1 from 7 to 9
+move 4 from 9 to 3
+move 8 from 8 to 7
+move 18 from 3 to 7
+move 20 from 7 to 8
+move 6 from 8 to 9
+move 6 from 5 to 1
+move 8 from 9 to 4
+move 3 from 5 to 4
+move 8 from 8 to 4
+move 2 from 5 to 2
+move 3 from 1 to 5
+move 4 from 3 to 7
+move 6 from 2 to 9
+move 3 from 3 to 6
+move 6 from 4 to 5
+move 2 from 6 to 3
+move 1 from 3 to 1
+move 4 from 3 to 8
+move 8 from 4 to 3
+move 4 from 3 to 7
+move 4 from 4 to 5
+move 4 from 9 to 5
+move 3 from 3 to 4
+move 3 from 4 to 9
+move 1 from 1 to 4
+move 2 from 1 to 5
+move 7 from 7 to 8
+move 4 from 7 to 4
+move 1 from 6 to 7
+move 1 from 1 to 5
+move 1 from 3 to 8
+move 11 from 5 to 9
+move 17 from 9 to 8
+move 13 from 8 to 4
+move 1 from 4 to 8
+move 4 from 7 to 1
+move 4 from 8 to 3
+move 6 from 5 to 4
+move 3 from 3 to 6
+move 2 from 1 to 9
+move 1 from 9 to 5
+move 1 from 3 to 5
+move 5 from 5 to 9
+move 2 from 1 to 8
+move 21 from 8 to 6
+move 2 from 8 to 4
+move 4 from 9 to 6
+move 1 from 9 to 7
+move 19 from 4 to 1
+move 28 from 6 to 5
+move 7 from 4 to 2
+move 28 from 5 to 3
+move 1 from 9 to 4
+move 1 from 4 to 2
+move 1 from 7 to 8
+move 1 from 8 to 9
+move 13 from 1 to 3
+move 8 from 2 to 8
+move 3 from 1 to 2
+move 5 from 8 to 5
+move 1 from 2 to 7
+move 1 from 9 to 7
+move 1 from 2 to 3
+move 2 from 7 to 9
+move 1 from 2 to 6
+move 1 from 9 to 1
+move 9 from 3 to 9
+move 3 from 9 to 1
+move 1 from 6 to 8
+move 21 from 3 to 7
+move 7 from 9 to 4
+move 2 from 4 to 2
+move 1 from 8 to 6
+move 7 from 1 to 4
+move 7 from 7 to 8
+move 4 from 5 to 9
+move 10 from 7 to 1
+move 7 from 3 to 9
+move 1 from 7 to 9
+move 1 from 5 to 3
+move 3 from 3 to 5
+move 10 from 4 to 2
+move 1 from 3 to 7
+move 2 from 4 to 9
+move 3 from 9 to 1
+move 3 from 7 to 1
+move 1 from 6 to 4
+move 1 from 1 to 2
+move 1 from 3 to 4
+move 2 from 4 to 3
+move 1 from 7 to 4
+move 4 from 8 to 9
+move 1 from 4 to 9
+move 3 from 1 to 9
+move 12 from 1 to 7
+move 2 from 9 to 5
+move 12 from 9 to 7
+move 5 from 5 to 1
+move 1 from 8 to 5
+move 4 from 1 to 4
+move 1 from 9 to 6
+move 1 from 3 to 4
+move 3 from 8 to 3
+move 1 from 1 to 7
+move 8 from 2 to 5
+move 2 from 8 to 1
+move 10 from 7 to 1
+move 4 from 9 to 5
+move 2 from 5 to 8
+move 11 from 5 to 4
+move 6 from 7 to 2
+move 2 from 2 to 1
+move 1 from 7 to 5
+move 1 from 5 to 1
+move 2 from 4 to 8
+move 1 from 6 to 9
+move 8 from 4 to 3
+move 8 from 1 to 7
+move 7 from 1 to 2
+move 4 from 3 to 9
+move 1 from 9 to 6
+move 7 from 2 to 1
+move 5 from 2 to 3
+move 2 from 7 to 8
+move 5 from 8 to 4
+move 2 from 9 to 3
+move 1 from 8 to 1
+move 6 from 3 to 5
+move 10 from 3 to 1
+move 3 from 5 to 3
+move 3 from 2 to 1
+move 1 from 5 to 4
+move 6 from 4 to 5
+move 1 from 6 to 2
+move 3 from 4 to 7
+move 1 from 9 to 4
+move 2 from 3 to 1
+move 1 from 9 to 8
+move 1 from 3 to 7
+move 4 from 4 to 8
+move 2 from 7 to 4
+move 8 from 5 to 9
+move 2 from 8 to 6
+move 2 from 4 to 3
+move 2 from 3 to 4
+move 4 from 9 to 7
+move 1 from 8 to 7
+move 2 from 6 to 9
+move 2 from 8 to 9
+move 1 from 2 to 9
+move 1 from 7 to 8
+move 1 from 2 to 7
+move 19 from 7 to 6
+move 1 from 8 to 1
+move 2 from 4 to 8
+move 5 from 6 to 1
+move 2 from 7 to 2
+move 2 from 2 to 8
+move 2 from 1 to 8
+move 4 from 8 to 2
+move 3 from 2 to 8
+move 6 from 9 to 5
+move 8 from 6 to 3
+move 26 from 1 to 6
+move 1 from 5 to 3
+move 1 from 1 to 5
+move 8 from 3 to 1
+move 1 from 3 to 7
+move 3 from 9 to 2
+move 4 from 2 to 6
+move 26 from 6 to 1
+move 1 from 7 to 5
+move 3 from 8 to 4
+move 2 from 8 to 2
+move 7 from 1 to 2
+move 1 from 5 to 9
+move 2 from 4 to 6
+move 9 from 6 to 2
+move 18 from 1 to 7
+move 6 from 7 to 1
+move 6 from 5 to 6
+move 1 from 1 to 2
+move 19 from 2 to 7
+move 1 from 4 to 2
+move 9 from 7 to 1
+move 3 from 6 to 7
+move 1 from 9 to 4
+move 1 from 2 to 3
+move 8 from 7 to 8
+move 4 from 6 to 5
+move 2 from 6 to 3
+move 1 from 4 to 2
+move 4 from 5 to 1
+move 8 from 8 to 7
+move 17 from 7 to 8
+move 3 from 3 to 1
+move 1 from 2 to 8
+move 8 from 8 to 4
+move 8 from 8 to 7
+move 1 from 8 to 2
+move 7 from 7 to 6
+move 1 from 2 to 7
+move 5 from 7 to 8
+move 7 from 1 to 6
+move 10 from 6 to 1
+move 4 from 7 to 9
+move 3 from 9 to 7
+move 1 from 7 to 2
+move 6 from 4 to 2
+move 7 from 1 to 5
+move 4 from 2 to 5
+move 16 from 1 to 9
+move 3 from 2 to 7
+move 2 from 4 to 9
+move 4 from 1 to 6
+move 5 from 7 to 4
+move 4 from 6 to 3
+move 1 from 7 to 4
+move 1 from 6 to 9
+move 1 from 8 to 5
+move 4 from 3 to 2
+move 2 from 5 to 3
+move 3 from 6 to 2
+move 3 from 2 to 1
+move 9 from 5 to 8
+move 1 from 3 to 1
+move 10 from 8 to 1
+move 1 from 8 to 5
+move 16 from 9 to 2
+move 1 from 3 to 2
+move 12 from 1 to 9
+move 1 from 9 to 2
+move 3 from 1 to 6
+move 2 from 1 to 9
+move 3 from 6 to 8
+move 20 from 2 to 7
+move 16 from 9 to 7
+move 1 from 7 to 5
+move 2 from 5 to 9
+move 2 from 2 to 3
+move 2 from 8 to 5
+move 3 from 9 to 7
+move 2 from 5 to 2
+move 1 from 4 to 6
+move 2 from 1 to 4
+move 23 from 7 to 5
+move 4 from 8 to 5
+move 7 from 7 to 1
+move 16 from 5 to 7
+move 1 from 6 to 5
+move 1 from 2 to 4
+move 2 from 3 to 9
+move 1 from 2 to 3
+move 13 from 5 to 1
+move 1 from 3 to 8
+move 1 from 9 to 4
+move 19 from 1 to 9
+move 2 from 1 to 9
+move 22 from 9 to 8
+move 14 from 8 to 5
+move 12 from 5 to 3
+move 21 from 7 to 9
+move 14 from 9 to 7
+move 1 from 8 to 6
+move 9 from 3 to 7
+move 1 from 3 to 2
+move 4 from 4 to 1
+move 1 from 2 to 4
+move 1 from 3 to 9
+move 6 from 8 to 9
+move 4 from 1 to 7
+move 2 from 5 to 9
+move 6 from 4 to 5
+move 4 from 7 to 4
+move 1 from 5 to 3
+move 5 from 9 to 7
+move 2 from 3 to 1
+move 6 from 9 to 6
+move 1 from 1 to 6
+move 2 from 4 to 2
+move 8 from 7 to 5
+move 20 from 7 to 5
+move 2 from 5 to 6
+move 4 from 9 to 5
+move 1 from 1 to 3
+move 1 from 3 to 4
+move 1 from 2 to 7
+move 1 from 4 to 9
+move 9 from 6 to 3
+move 2 from 4 to 3
+move 28 from 5 to 3
+move 1 from 8 to 3
+move 1 from 8 to 1
+move 1 from 2 to 8
+move 1 from 6 to 2
+move 1 from 8 to 1
+move 6 from 5 to 7
+move 1 from 5 to 1
+move 1 from 9 to 2
+move 1 from 1 to 3
+move 1 from 9 to 7
+move 2 from 1 to 2
+move 11 from 3 to 8
+move 3 from 8 to 6
+move 3 from 6 to 9
+move 25 from 3 to 7
+move 4 from 3 to 8
+move 4 from 2 to 3
+move 9 from 8 to 9
+move 2 from 3 to 7
+move 3 from 8 to 2
+move 11 from 9 to 7
+move 1 from 9 to 1
+move 4 from 7 to 3
+move 1 from 1 to 5
+move 23 from 7 to 2
+move 12 from 2 to 3
+move 2 from 3 to 9
+move 12 from 2 to 1
+move 2 from 3 to 9
+move 1 from 5 to 4
+move 1 from 2 to 5
+move 1 from 9 to 4
+move 1 from 5 to 9
+move 2 from 4 to 2
+move 3 from 1 to 4
+move 1 from 2 to 1
+move 10 from 3 to 2
+move 7 from 7 to 3
+move 11 from 7 to 9
+move 5 from 3 to 1
+move 1 from 4 to 5
+move 11 from 2 to 3
+move 9 from 9 to 3
+move 3 from 9 to 4
+move 2 from 4 to 8
+move 1 from 5 to 6
+move 13 from 1 to 5
+move 3 from 3 to 8
+move 3 from 7 to 2
+move 1 from 7 to 4
+move 3 from 8 to 3
+move 8 from 3 to 8
+move 4 from 4 to 5
+move 2 from 8 to 2
+move 8 from 8 to 3
+move 1 from 6 to 3
+move 2 from 2 to 8
+move 6 from 5 to 2
+move 3 from 2 to 8
+move 1 from 1 to 7
+move 2 from 9 to 3
+move 3 from 5 to 4
+move 2 from 8 to 6

2022/go/05/sample1

@@ -0,0 +1,9 @@
+    [D]    
+[N] [C]    
+[Z] [M] [P]
+ 1   2   3 
+
+move 1 from 2 to 1
+move 3 from 1 to 3
+move 2 from 2 to 1
+move 1 from 1 to 2

README.md

@@ -0,0 +1,32 @@
+# Advent of Code
+
+## What is it?
+
+> from the [adventofcode.com/about](https://adventofcode.com/2022/about)
+
+Advent of Code is an Advent calendar (written by [Eric Wastl](http://was.tl/))
+of small programming puzzles for a variety of skill sets and skill levels that
+can be solved in any programming language you like.
+
+## Why is it?
+
+People use them as interview prep, company training, university coursework,
+practice problems, a speed contest, or to challenge each other. 
+
+Personally, I started using it as a hobby, but then, after hearing [ThePrimeagen
+saying it was a great idea to use it as a way to learn a new programming
+language](https://www.youtube.com/watch?v=E8cM12jRH7k), I started doing the
+challenges to learn the `go` programming language, because why not?
+
+## What can you find here?
+
+In this repository you can find my solutions to the years 2020, 2021 and 2022.
+I've never completed an entire Advent of Code calendar because the final
+puzzles are usually pretty hard and I didn't (and still don't) have time to
+obsess about them. I try to keep this as a fun experience to solve problems and
+learn new things, nothing too hardcore.
+
+## Questions
+
+If you have any questions about my solutions, feel free to create an issue and
+I'll try to answer it :)