|
|
@@ -0,0 +1,67 @@
|
|
|
+package main
|
|
|
+
|
|
|
+import (
|
|
|
+ "bufio"
|
|
|
+ "fmt"
|
|
|
+ "log"
|
|
|
+ "os"
|
|
|
+ "slices"
|
|
|
+)
|
|
|
+
|
|
|
+func readInput(file *os.File) ([]int, []int) {
|
|
|
+ scanner := bufio.NewScanner(file)
|
|
|
+ var lefts, rights []int
|
|
|
+
|
|
|
+ for scanner.Scan() {
|
|
|
+ line := scanner.Text()
|
|
|
+ if line == "" {
|
|
|
+ break
|
|
|
+ }
|
|
|
+
|
|
|
+ var left, right int
|
|
|
+ n, err := fmt.Sscanf(line, "%d %d", &left, &right)
|
|
|
+ if n != 2 || err != nil {
|
|
|
+ log.Fatalf("Bad input: %s", line)
|
|
|
+ }
|
|
|
+
|
|
|
+ lefts = append(lefts, left)
|
|
|
+ rights = append(rights, right)
|
|
|
+ }
|
|
|
+
|
|
|
+ return lefts, rights
|
|
|
+}
|
|
|
+
|
|
|
+func abs(a int) int {
|
|
|
+ if a < 0 {
|
|
|
+ return -a
|
|
|
+ }
|
|
|
+
|
|
|
+ return a
|
|
|
+}
|
|
|
+
|
|
|
+func part1(lefts, rights []int) int {
|
|
|
+ slices.Sort(lefts)
|
|
|
+ slices.Sort(rights)
|
|
|
+
|
|
|
+ var distance int
|
|
|
+ for i := range lefts {
|
|
|
+ distance += abs(rights[i] - lefts[i])
|
|
|
+ }
|
|
|
+
|
|
|
+ return distance
|
|
|
+}
|
|
|
+
|
|
|
+func main() {
|
|
|
+ if len(os.Args) < 2 {
|
|
|
+ log.Fatal("You need to specify a file!")
|
|
|
+ }
|
|
|
+
|
|
|
+ filePath := os.Args[1]
|
|
|
+ file, err := os.Open(filePath)
|
|
|
+ if err != nil {
|
|
|
+ log.Fatalf("Failed to open %s!\n", filePath)
|
|
|
+ }
|
|
|
+
|
|
|
+ lefts, rights := readInput(file)
|
|
|
+ fmt.Println("Part1:", part1(lefts, rights))
|
|
|
+}
|
