package main import ( "bufio" _ "embed" "fmt" "strings" aoc "go.sour.is/advent-of-code" "golang.org/x/exp/maps" ) // var log = aoc.Log func main() { aoc.MustResult(aoc.Runner(run)) } type result struct { valuePT1 int valuePT2 int } func (r result) String() string { return fmt.Sprintf("%#v", r) } func run(scan *bufio.Scanner) (*result, error) { var maplist []Map var m Map for scan.Scan() { text := scan.Text() if len(text) == 0 { maplist = append(maplist, m) m = Map{} } m = append(m, []rune(text)) } maplist = append(maplist, m) score1 := 0 for _, m := range maplist { m = aoc.Transpose(reverse(m)) m.Sort() score1 += m.Score() } score2 := 0 type record [5]int var current record memo := make(map[record]int) for _, m := range maplist { // fmt.Println(m) m = aoc.Transpose(reverse(m)) for i := 0; i < 1_000_000_000; i++ { m, current = cycle(m) v, ok := memo[current] if ok && v > 1 { counts := aoc.Reduce( func(i int, v int, counts [3]int) [3]int { counts[v]++ return counts }, [3]int{}, maps.Values(memo)...) // fmt.Println(i, counts) i = 1_000_000_000 - (1_000_000_000-counts[0]-counts[1])%counts[2] clear(memo) } memo[current] += 1 // fmt.Println(i, current, v) } score2 += m.Score() } return &result{valuePT1: score1, valuePT2: score2}, nil } type Map [][]rune func (m Map) String() string { var buf strings.Builder for _, row := range m { buf.WriteString(string(row)) buf.WriteRune('\n') } buf.WriteRune('\n') return buf.String() } func (m *Map) Sort() { if m == nil { return } for _, row := range *m { base := 0 for i, r := range row { if r == '#' { base = i + 1 continue } if r == 'O' { if base < i { row[base], row[i] = row[i], row[base] } base++ } } } } func (m *Map) Score() int { if m == nil { return 0 } sum := 0 max := len(*m) for _, row := range *m { for i, r := range row { if r == 'O' { sum += max - i } } } return sum } func reverse(m Map) Map { for _, row := range m { aoc.Reverse(row) } return m } func cycle(m Map) (Map, [5]int) { var current [5]int m.Sort() current[0] = m.Score() m = aoc.Transpose(reverse(m)) m.Sort() current[1] = m.Score() m = aoc.Transpose(reverse(m)) m.Sort() current[2] = m.Score() m = aoc.Transpose(reverse(m)) m.Sort() current[3] = m.Score() m = aoc.Transpose(reverse(m)) current[4] = m.Score() return m, current }