92 lines
1.7 KiB
Go
92 lines
1.7 KiB
Go
package dayone
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import (
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"os"
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"strconv"
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"strings"
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"advent-of-code/internal/registry"
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)
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func init() {
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registry.Register("2016D1", ParseInput, PartOne, PartTwo)
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}
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type position struct {
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x, y int
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}
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func abs(n int) int {
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if n < 0 {
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return -n
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}
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return n
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}
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func ParseInput(filepath string) []string {
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content, _ := os.ReadFile(filepath)
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parts := strings.Split(string(content), ",")
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for i, p := range parts {
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parts[i] = strings.TrimSpace(p)
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}
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return parts
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}
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func PartOne(data []string) int {
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x, y := 0, 0
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directions := [][]int{{0, 1}, {1, 0}, {0, -1}, {-1, 0}}
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currentDirection := 0
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for _, instruction := range data {
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turn := instruction[0]
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distance, _ := strconv.Atoi(instruction[1:])
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switch turn {
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case 'R':
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currentDirection = (currentDirection + 1) % 4
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case 'L':
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currentDirection = (currentDirection + 3) % 4
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}
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x += directions[currentDirection][0] * distance
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y += directions[currentDirection][1] * distance
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}
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return abs(x) + abs(y)
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}
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func PartTwo(data []string) int {
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x, y := 0, 0
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directions := [][]int{{0, 1}, {1, 0}, {0, -1}, {-1, 0}}
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currentDirection := 0
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visited := make(map[position]bool)
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visited[position{0, 0}] = true
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for _, instruction := range data {
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turn := instruction[0]
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distance, _ := strconv.Atoi(instruction[1:])
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switch turn {
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case 'R':
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currentDirection = (currentDirection + 1) % 4
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case 'L':
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currentDirection = (currentDirection + 3) % 4
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}
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directionX := directions[currentDirection][0]
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directionY := directions[currentDirection][1]
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for range distance {
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x += directionX
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y += directionY
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pos := position{x, y}
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if visited[pos] {
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return abs(x) + abs(y)
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}
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visited[pos] = true
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}
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}
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return 0
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}
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