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@@ -0,0 +1,75 @@
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+package main
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+
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+import (
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+ "bufio"
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+ "fmt"
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+ "log"
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+ "os"
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+)
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+
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+type Rotation struct {
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+ Direction byte
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+ Clicks int
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+}
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+
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+func readInput(file *os.File) []Rotation {
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+ scanner := bufio.NewScanner(file)
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+ var rotations []Rotation
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+
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+ for scanner.Scan() {
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+ line := scanner.Text()
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+ if line == "" {
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+ break
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+ }
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+
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+ var direction byte
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+ var clicks int
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+ n, err := fmt.Sscanf(line, "%c%d", &direction, &clicks)
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+ if n != 2 || err != nil {
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+ log.Fatalf("Bad input: %s", line)
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+ }
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+
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+ rotations = append(rotations, Rotation{Direction: direction, Clicks: clicks})
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+ }
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+
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+ return rotations
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+}
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+
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+func part1(rotations []Rotation) int {
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+ var zeros int
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+ dial := 50
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+
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+ for _, rotation := range rotations {
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+ if rotation.Direction == 'L' {
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+ dial -= rotation.Clicks
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+ } else {
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+ dial += rotation.Clicks
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+ }
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+
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+ dial %= 100
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+ if dial < 0 {
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+ dial += 100
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+ }
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+
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+ if dial == 0 {
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+ zeros++
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+ }
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+ }
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+
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+ return zeros
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+}
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+
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+func main() {
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+ if len(os.Args) < 2 {
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+ log.Fatal("You need to specify a file!")
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+ }
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+
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+ filePath := os.Args[1]
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+ file, err := os.Open(filePath)
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+ if err != nil {
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+ log.Fatalf("Failed to open %s!\n", filePath)
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+ }
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+
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+ rotations := readInput(file)
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+ fmt.Println("Part1:", part1(rotations))
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+}
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