day17: start solving part 1

Author: fxnn

day18/example.txt

@@ -0,0 +1,25 @@
+5,4
+4,2
+4,5
+3,0
+2,1
+6,3
+2,4
+1,5
+0,6
+3,3
+2,6
+5,1
+1,2
+5,5
+2,5
+6,5
+1,4
+0,4
+6,4
+1,1
+6,1
+1,0
+0,5
+1,6
+2,0

day18/main.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"os"
+	"regexp"
+
+	"github.com/fxnn/adventofcode2024/util"
+)
+
+const (
+	CORRUPTED = -1
+)
+
+func printSpace(space [][]int) {
+	for y := range space {
+		for x := range space[y] {
+			fmt.Printf("%2d ", space[y][x])
+		}
+		fmt.Println()
+	}
+	fmt.Println()
+}
+
+func main() {
+	var size = flag.Int("max", 70, "coordinates have range [0,max]")
+	var count = flag.Int("count", 1024, "number of bytes that have fallen")
+	flag.Parse()
+	var space = make([][]int, *size+1)
+	for y := range space {
+		space[y] = make([]int, *size+1)
+	}
+
+	var scanner = bufio.NewScanner(os.Stdin)
+	var pattern = regexp.MustCompile(`^(\d+),(\d+)$`)
+
+	var fallen int
+	for scanner.Scan() && fallen < *count {
+		var line = scanner.Text()
+		var matches = pattern.FindStringSubmatch(line)
+		var x, y int
+		if len(matches) > 0 {
+			x = util.Atoi(matches[1])
+			y = util.Atoi(matches[2])
+			space[y][x] = CORRUPTED
+			fallen++
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %s\n", err)
+		os.Exit(1)
+	}
+
+	printSpace(space)
+}