107 lines
1.9 KiB
Go
107 lines
1.9 KiB
Go
package dayseven
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import (
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"os"
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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("2025D7", ParseInput, PartOne, PartTwo)
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}
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type Position struct {
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row int
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column int
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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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return strings.Split(string(content), "\n")
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}
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func findStart(data []string) (int, int) {
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for row := range data {
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if column := strings.IndexByte(data[row], 'S'); column != -1 {
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return row, column
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}
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}
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return -1, -1
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}
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func PartOne(data []string) int {
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rows, columns := len(data), len(data[0])
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startRow, startColumn := findStart(data)
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queue := []Position{{startRow, startColumn}}
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activated := make(map[Position]bool)
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splits := 0
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for len(queue) > 0 {
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current := queue[0]
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queue = queue[1:]
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row := current.row + 1
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column := current.column
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for row < rows && data[row][column] != '^' {
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row++
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}
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if row < rows {
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splitPosition := Position{row, column}
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if !activated[splitPosition] {
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activated[splitPosition] = true
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splits++
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if column > 0 {
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queue = append(queue, Position{row, column - 1})
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}
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if column < columns-1 {
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queue = append(queue, Position{row, column + 1})
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}
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}
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}
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}
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return splits
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}
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func PartTwo(input []string) int {
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rows, columns := len(input), len(input[0])
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startRow, startColumn := findStart(input)
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cache := make(map[Position]int)
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var countTimelines func(row, column int) int
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countTimelines = func(row, column int) int {
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position := Position{row, column}
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if count, exists := cache[position]; exists {
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return count
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}
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r, c := row+1, column
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for r < rows && input[r][c] != '^' {
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r++
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}
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if r == rows {
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return 1
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}
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total := 0
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if c > 0 {
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total += countTimelines(r, c-1)
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}
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if c < columns-1 {
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total += countTimelines(r, c+1)
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}
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cache[position] = total
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return total
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}
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return countTimelines(startRow, startColumn)
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}
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