dumping 5 days of unrefined solutions :)

2022/day05/main.go

@@ -0,0 +1,126 @@
+package main
+
+import (
+	_ "embed"
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/alexchao26/advent-of-code-go/util"
+)
+
+//go:embed input.txt
+var input string
+
+func init() {
+	// do this in init (not main) so test file has same input
+	input = strings.TrimRight(input, "\n")
+	if len(input) == 0 {
+		panic("empty input.txt file")
+	}
+}
+
+func main() {
+	var part int
+	flag.IntVar(&part, "part", 1, "part 1 or 2")
+	flag.Parse()
+	fmt.Println("Running part", part)
+
+	if part == 1 {
+		ans := part1(input)
+		util.CopyToClipboard(fmt.Sprintf("%v", ans))
+		fmt.Println("Output:", ans)
+	} else {
+		ans := part2(input)
+		util.CopyToClipboard(fmt.Sprintf("%v", ans))
+		fmt.Println("Output:", ans)
+	}
+}
+
+func part1(input string) string {
+	stacks, steps := parseInput(input)
+
+	for _, step := range steps {
+		// move crates ONE AT A TIME
+		for q := 0; q < step.qty; q++ {
+			top := stacks[step.from][len(stacks[step.from])-1]
+			stacks[step.to] = append(stacks[step.to], top)
+			stacks[step.from] = stacks[step.from][:len(stacks[step.from])-1]
+		}
+	}
+
+	ans := ""
+	for _, stack := range stacks {
+		ans += stack[len(stack)-1]
+	}
+	return ans
+}
+
+func part2(input string) string {
+	stacks, steps := parseInput(input)
+
+	for _, step := range steps {
+		// move crates ONCE
+		fromIndex := len(stacks[step.from]) - step.qty
+		stacks[step.to] = append(stacks[step.to], stacks[step.from][fromIndex:]...)
+		stacks[step.from] = stacks[step.from][:fromIndex]
+	}
+
+	ans := ""
+	for _, stack := range stacks {
+		ans += stack[len(stack)-1]
+	}
+	return ans
+}
+
+// move 4 from 3 to 1
+type step struct {
+	qty, from, to int
+}
+
+func (s step) String() string {
+	return fmt.Sprintf("move %d from %d to %d", s.qty, s.from, s.to)
+}
+
+func parseInput(input string) ([][]string, []step) {
+	parts := strings.Split(input, "\n\n")
+
+	state := parts[0]
+	oversized := [][]string{}
+	for _, row := range strings.Split(state, "\n") {
+		oversized = append(oversized, strings.Split(row, ""))
+	}
+	oRows, oCols := len(oversized), len(oversized[0])
+
+	actual := [][]string{}
+
+	for c := 0; c < oCols-1; c++ {
+		if oversized[oRows-1][c] != " " {
+			// hit a column with values... move up from here
+			stack := []string{}
+			for r := oRows - 2; r >= 0; r-- {
+				char := oversized[r][c]
+				if char != " " {
+					stack = append(stack, char)
+				}
+			}
+			actual = append(actual, stack)
+		}
+	}
+
+	stepsRaw := parts[1]
+	steps := []step{}
+	for _, row := range strings.Split(stepsRaw, "\n") {
+		inst := step{}
+		_, err := fmt.Sscanf(row, "move %d from %d to %d", &inst.qty, &inst.from, &inst.to)
+		if err != nil {
+			panic(err)
+		}
+		// subtract one so they're zero indexed...
+		inst.from--
+		inst.to--
+		steps = append(steps, inst)
+	}
+
+	return actual, steps
+}