fotonmoton/aoc21
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

refactor d9

Browse source
This commit is contained in:
Gregory 2022-02-22 01:54:17 +02:00
parent b5444e5aa5
commit 0338b14930
2 changed files with 16 additions and 28 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

7
d9/common.go
View file

@ -5,11 +5,12 @@ import (
"strings" "strings"
) )
const wall = '9'
func addWalls(lines []string) []string { func addWalls(lines []string) []string {
for i, line := range lines { for i, line := range lines {
lines[i] = fmt.Sprintf("9%v9", line) lines[i] = fmt.Sprintf("%v%v%v", string(wall), line, string(wall))
} }
nines := strings.Repeat(string(wall), len(lines[0]))
nines := strings.Repeat("9", len(lines[0]))
return append([]string{nines}, append(lines, nines)...) return append([]string{nines}, append(lines, nines)...)
} }

37
d9/p2.go
View file

@ -5,54 +5,41 @@ import (
"strings" "strings"
) )
type exists struct{}
type pos struct { type pos struct {
x int x int
y int y int
} }
type basin map[pos]exists type basin map[pos]bool
const wall = '9' func flood(x, y int, heights []string, basin basin, flooded basin) basin {
func flooded(x, y int, basins []basin) bool {
for _, basin := range basins {
if _, ok := basin[pos{x, y}]; ok {
return true
}
}
return false
}
func flood(x, y int, heights []string, basin basin) basin {
if heights[y][x] == wall { if heights[y][x] == wall {
return basin return basin
} }
if _, ok := basin[pos{x, y}]; ok { if flooded[pos{x, y}] {
return basin return basin
} }
basin[pos{x, y}] = exists{} basin[pos{x, y}] = true
flooded[pos{x, y}] = true
flood(x, y-1, heights, basin, flooded)
flood(x+1, y, heights, basin, flooded)
flood(x, y+1, heights, basin, flooded)
flood(x-1, y, heights, basin, flooded)
flood(x, y-1, heights, basin)
flood(x+1, y, heights, basin)
flood(x, y+1, heights, basin)
flood(x-1, y, heights, basin)
return basin return basin
} }
func P2(in string) int { func P2(in string) int {
heights := addWalls(strings.Split(strings.TrimSpace(in), "\n")) heights := addWalls(strings.Split(strings.TrimSpace(in), "\n"))
basins := []basin{} basins := []basin{}
flooded := basin{}
for y := 1; y < len(heights)-1; y++ { for y := 1; y < len(heights)-1; y++ {
for x := 1; x < len(heights[0])-1; x++ { for x := 1; x < len(heights[0])-1; x++ {
if !flooded(x, y, basins) && heights[y][x] != wall { basins = append(basins, flood(x, y, heights, basin{}, flooded))
basins = append(basins, flood(x, y, heights, basin{}))
}
} }
} }