Day 18

day18/common/lava.go

@@ -0,0 +1,139 @@
+package common
+
+import (
+	"bufio"
+	"math"
+	"strconv"
+	"strings"
+)
+
+
+type Cube struct {
+  x, y, z int
+}
+
+
+type Grid struct {
+  cubes map[Cube]struct{}
+  outsideCubes map[Cube]struct{}
+  exposedFaces int
+  insideFaces int
+  minX, maxX, minY, maxY, minZ, maxZ int
+}
+
+func (grid *Grid) AddCube(x, y, z int) {
+  grid.cubes[Cube{x, y, z}] = struct{}{}
+  grid.exposedFaces += 6
+  grid.exposedFaces -= 2 * grid.GetCoveredFaces(x, y, z)
+
+  if x <= grid.minX {
+    grid.minX = x - 1
+  }
+  if x >= grid.maxX {
+    grid.maxX = x + 1
+  }
+  if y <= grid.minY {
+    grid.minY = y - 1
+  }
+  if y >= grid.maxY {
+    grid.maxY = y + 1
+  }
+  if z <= grid.minZ {
+    grid.minZ = z - 1
+  }
+  if z >= grid.maxZ {
+    grid.maxZ = z + 1
+  }
+}
+
+func (grid *Grid) PropagateWater(cube Cube, visited map[Cube]struct{}) {
+  grid.outsideCubes[cube] = struct{}{}
+
+  visited2 := make(map[Cube]struct{})
+  visited2[cube] = struct{}{}
+  
+  cubes := []Cube{{cube.x-1, cube.y, cube.z}, {cube.x+1, cube.y, cube.z},
+                  {cube.x, cube.y-1, cube.z}, {cube.x, cube.y+1, cube.z},
+                  {cube.x, cube.y, cube.z-1}, {cube.x, cube.y, cube.z+1}}
+  for _, cube2 := range cubes {
+    if _, ok := grid.cubes[cube2]; !ok && cube2.x >= grid.minX && cube2.x <= grid.maxX && 
+                                   cube2.y >= grid.minY && cube2.y <= grid.maxY && cube2.z >= grid.minZ && cube2.z <= grid.maxZ {
+      if _, ok := visited[cube2]; !ok {
+        if _, ok := grid.outsideCubes[cube2]; !ok {
+          for c := range(visited) {
+            visited2[c] = visited[c]
+          }
+          grid.PropagateWater(cube2, visited2)
+        }
+      }
+    }
+  }
+}
+
+func (grid *Grid) GetInsideFaces(cube Cube) int {
+  cubes := []Cube{{cube.x-1, cube.y, cube.z}, {cube.x+1, cube.y, cube.z},
+                  {cube.x, cube.y-1, cube.z}, {cube.x, cube.y+1, cube.z},
+                  {cube.x, cube.y, cube.z-1}, {cube.x, cube.y, cube.z+1}}
+  nFaces := 0
+  for _, cube := range cubes {
+    if _, ok := grid.cubes[cube]; !ok {
+      if _, ok := grid.outsideCubes[cube]; !ok {
+        nFaces++
+      }
+    }
+  }
+  return nFaces
+}
+
+func (grid *Grid) GetCoveredFaces(x, y, z int) int {
+  coveredFaces := 0
+  if _, found := grid.cubes[Cube{x-1, y, z}]; found {
+    coveredFaces += 1
+  }
+  if _, found := grid.cubes[Cube{x+1, y, z}]; found {
+    coveredFaces += 1
+  }
+  if _, found := grid.cubes[Cube{x, y-1, z}]; found {
+    coveredFaces += 1
+  }
+  if _, found := grid.cubes[Cube{x, y+1, z}]; found {
+    coveredFaces += 1
+  }
+  if _, found := grid.cubes[Cube{x, y, z-1}]; found {
+    coveredFaces += 1
+  }
+  if _, found := grid.cubes[Cube{x, y, z+1}]; found {
+    coveredFaces += 1
+  }
+  return coveredFaces
+}
+
+func (grid *Grid) GetTotalExposedFaces() int {
+  return grid.exposedFaces
+}
+
+func (grid *Grid) GetTotalOutsideArea() int {
+  return grid.exposedFaces - grid.insideFaces
+}
+
+
+func Parse(scanner bufio.Scanner) Grid {
+  grid := Grid{make(map[Cube]struct{}), make(map[Cube]struct{}), 0, 0,
+               math.MaxInt32, math.MinInt32, math.MaxInt32, math.MinInt32, math.MaxInt32, math.MinInt32}
+
+  for scanner.Scan() {
+    line := scanner.Text()
+    splittedLine := strings.Split(line, ",")
+    x, _ := strconv.Atoi(splittedLine[0])
+    y, _ := strconv.Atoi(splittedLine[1])
+    z, _ := strconv.Atoi(splittedLine[2])
+    grid.AddCube(x, y, z)
+  }
+
+  grid.PropagateWater(Cube{grid.minX, grid.minY, grid.minZ}, make(map[Cube]struct{}))
+  for cube := range(grid.cubes) {
+    grid.insideFaces += grid.GetInsideFaces(cube)
+  }
+
+  return grid
+}

day18/ex1/main.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+  "aoc2022/day18/common"
+  "bufio"
+  "fmt"
+  "os"
+)
+
+func main() {
+  grid := common.Parse(*bufio.NewScanner(os.Stdin))
+
+  fmt.Println(grid.GetTotalExposedFaces())
+}

day18/ex2/main.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"aoc2022/day18/common"
+	"bufio"
+	"fmt"
+	"os"
+)
+
+func main() {
+  grid := common.Parse(*bufio.NewScanner(os.Stdin))
+
+  fmt.Println(grid.GetTotalOutsideArea())
+}