Add day 14 part 1 solution

This is a bit messy but I was expecting a twist in part 2

day14/main.go

@@ -0,0 +1,133 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"slices"
+	"strings"
+)
+
+type Tile int
+
+const (
+	TileEmpty Tile = iota
+	TileRoundRock
+	TileCubeRock
+)
+
+func main() {
+	if len(os.Args) != 2 && len(os.Args) != 3 {
+		fmt.Fprintf(os.Stderr, "Usage: %s inputfile\n", os.Args[0])
+		os.Exit(1)
+	}
+
+	inputFilename := os.Args[1]
+	inputFile, err := os.Open(inputFilename)
+	if err != nil {
+		panic(fmt.Sprintf("could not open input file: %s", err))
+	}
+
+	defer inputFile.Close()
+
+	inputBytes, err := io.ReadAll(inputFile)
+	if err != nil {
+		panic(fmt.Sprintf("could not read input file: %s", err))
+	}
+
+	input := strings.TrimSpace(string(inputBytes))
+	inputLines := strings.Split(input, "\n")
+	grid, err := parseTileGrid(inputLines)
+	if err != nil {
+		panic(fmt.Sprintf("failed to parse input: %s", err))
+	}
+
+	fmt.Printf("Part 1: %d\n", part1(Clone2D(grid)))
+}
+
+func part1(inputGrid [][]Tile) int {
+	rollNorth(inputGrid)
+	load := 0
+	for row, rowItems := range inputGrid {
+		for _, tile := range rowItems {
+			if tile == TileRoundRock {
+				load += len(inputGrid) - row
+			}
+		}
+	}
+
+	return load
+}
+
+func rollNorth(inputGrid [][]Tile) {
+	for row, line := range inputGrid {
+		if row == 0 {
+			continue
+		}
+
+		for col, tile := range line {
+			if tile != TileRoundRock {
+				continue
+			}
+
+			lastEmptyRow := row
+			for candidateRow := row - 1; candidateRow >= 0; candidateRow-- {
+				if inputGrid[candidateRow][col] == TileEmpty {
+					lastEmptyRow = candidateRow
+				} else {
+					break
+				}
+			}
+
+			inputGrid[row][col] = TileEmpty
+			inputGrid[lastEmptyRow][col] = TileRoundRock
+		}
+	}
+}
+
+func Clone2D[T any, S ~[][]T](grid S) S {
+	clone := make(S, len(grid))
+	for i, row := range grid {
+		clone[i] = slices.Clone(row)
+	}
+
+	return clone
+}
+
+func parseTileGrid(inputLines []string) ([][]Tile, error) {
+	if len(inputLines) == 0 {
+		return [][]Tile{}, nil
+	}
+
+	grid := make([][]Tile, len(inputLines))
+	for i, line := range inputLines {
+		if len(line) != len(inputLines[0]) {
+			return nil, errors.New("lines have uneven lengths")
+		}
+
+		for _, char := range line {
+			tile, err := tileForRune(char)
+			if err != nil {
+				return nil, err
+			}
+
+			grid[i] = append(grid[i], tile)
+		}
+	}
+
+	return grid, nil
+}
+
+func tileForRune(r rune) (Tile, error) {
+	switch r {
+	case '.':
+		return TileEmpty, nil
+	case 'O':
+		return TileRoundRock, nil
+	case '#':
+		return TileCubeRock, nil
+	default:
+		return TileEmpty, fmt.Errorf("invalid tile char %c", r)
+	}
+}