AoC Day 3, Part 1 (Solved)

2023/03/code.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"strconv"
+	"strings"
+	"unicode"
+
+	"github.com/jpillora/puzzler/harness/aoc"
+)
+
+func main() {
+	aoc.Harness(run)
+}
+
+func getNumberAndBlank(schema [][]rune, x int, y int) int {
+	if x < 0 || x >= len(schema) || y < 0 || y >= len(schema[x]) {
+		// Out of bounds
+		return 0
+	}
+
+	if !unicode.IsNumber(schema[x][y]) {
+		// Not a number to start
+		return 0
+	}
+
+	// Moves along y to find the first character...
+	firstFound := false
+	for !firstFound {
+		if y == 0 || !unicode.IsNumber(schema[x][y-1]) {
+			firstFound = true
+		} else {
+			y -= 1
+		}
+	}
+
+	// then assemble
+	numStr := ""
+	for y < len(schema[x]) && unicode.IsNumber(schema[x][y]) {
+		numStr += string(schema[x][y])
+		schema[x][y] = '.'
+		y += 1
+	}
+
+	num, _ := strconv.Atoi(numStr)
+
+	return num
+}
+
+// on code change, run will be executed 4 times:
+// 1. with: false (part1), and example input
+// 2. with: true (part2), and example input
+// 3. with: false (part1), and user input
+// 4. with: true (part2), and user input
+// the return value of each run is printed to stdout
+func run(part2 bool, input string) any {
+	// Assemble schematic
+	schematic := make([][]rune, 0)
+	for _, line := range strings.Split(input, "\n") {
+		if line != "" {
+			schematic = append(schematic, []rune(line))
+		}
+	}
+
+	// when you're ready to do part 2, remove this "not implemented" block
+	if part2 {
+		return "not implemented"
+	}
+	// solve part 1 here
+
+	// Go through array, if we find a non-number non-period, find all adjacent numbers and then turn those to periods
+	engineSum := 0
+	for x, _ := range schematic {
+		for y, _ := range schematic[x] {
+			if unicode.IsNumber(schematic[x][y]) || schematic[x][y] == '.' {
+				continue
+			}
+
+			// Else, it's a symbol! Go around and, if there are any numbers, assemble them
+			for xi := x - 1; xi < x+2; xi++ {
+				for yi := y - 1; yi < y+2; yi++ {
+					engineSum += getNumberAndBlank(schematic, xi, yi)
+				}
+			}
+
+		}
+	}
+
+	return engineSum
+}