Day 17

day17/common/tetris.go

@@ -0,0 +1,296 @@
+package common
+
+import (
+	"bufio"
+	"fmt"
+)
+
+
+type Rock byte
+
+const (
+  Minus Rock = iota
+  Plus
+  Angle
+  Line
+  Square
+)
+
+func GetRock(rockType int) Rock {
+  switch rockType {
+    case 0:
+      return Minus
+    case 1:
+      return Plus
+    case 2:
+      return Angle
+    case 3:
+      return Line
+    case 4:
+      return Square
+  }
+  return Minus
+}
+
+
+type Tile byte
+
+const (
+  Empty Tile = iota
+  MovingRock
+  StoppedRock
+)
+
+
+type PreviousAction struct {
+  endJet int
+  heightDifference int
+}
+
+
+type Chamber struct {
+  tiles [][]Tile
+  highestPoint int
+  offset int
+  nRocks int
+  jets []Jet
+  currentJet int
+  cache map[Rock]map[int]PreviousAction
+}
+
+func NewChamber(jets []Jet) *Chamber {
+  return &Chamber{[][]Tile{}, -1, 0, 0, jets, 0, make(map[Rock]map[int]PreviousAction)}
+}
+
+func (chamber Chamber) Clone() *Chamber {
+  return &Chamber{[][]Tile{}, -1, 0, 0, chamber.jets, 0, make(map[Rock]map[int]PreviousAction)}
+}
+
+func (chamber *Chamber) DropRock() {
+  for i := len(chamber.tiles); i <= chamber.highestPoint + 7 - chamber.offset; i++ {
+    chamber.tiles = append(chamber.tiles, []Tile{Empty, Empty, Empty, Empty, Empty, Empty, Empty})
+  }
+
+  newRock := GetRock(chamber.nRocks % 5)
+  chamber.nRocks++
+  startJet := chamber.currentJet
+  currHighestPoint := chamber.highestPoint - chamber.offset
+
+  switch newRock {
+    case Minus:
+      chamber.tiles[len(chamber.tiles) - 4][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 4][3] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 4][4] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 4][5] = MovingRock
+    case Plus:
+      chamber.tiles[len(chamber.tiles) - 4][3] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][3] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][4] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 2][3] = MovingRock
+    case Angle:
+      chamber.tiles[len(chamber.tiles) - 4][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 4][3] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 4][4] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][4] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 2][4] = MovingRock
+    case Line:
+      chamber.tiles[len(chamber.tiles) - 4][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 2][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 1][2] = MovingRock
+    case Square:
+      chamber.tiles[len(chamber.tiles) - 4][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 4][3] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][2] = MovingRock
+      chamber.tiles[len(chamber.tiles) - 3][3] = MovingRock
+  }
+
+  moving := true
+  for moving {
+    canShift := true
+    jet := chamber.jets[chamber.currentJet]
+    chamber.currentJet = (chamber.currentJet + 1) % len(chamber.jets)
+
+    rowsChecked := 0
+    var lowestPoint int
+    for i := len(chamber.tiles) - 1; i >= 0 && rowsChecked != 0b01111111; i-- {
+      for j := 0; j < len(chamber.tiles[i]); j++ {
+        if chamber.tiles[i][j] == MovingRock {
+          if jet == LeftToRight {
+            if j == 6 || chamber.tiles[i][j+1] == StoppedRock {
+              canShift = false
+            }
+          } else if jet == RightToLeft {
+            if j == 0 || chamber.tiles[i][j-1] == StoppedRock {
+              canShift = false
+            }
+          }
+        } else if chamber.tiles[i][j] == StoppedRock {
+          rowsChecked |= 0b01 << j
+        }
+      }
+      if rowsChecked == 0b01111111 {
+        lowestPoint = i
+      }
+    }
+
+    for i := lowestPoint; i < len(chamber.tiles); i++ {
+      if jet == LeftToRight {
+        for j := len(chamber.tiles[i]) - 1; j >= 0; j-- {
+          if chamber.tiles[i][j] == MovingRock {
+            if canShift {
+              chamber.tiles[i][j] = Empty
+              chamber.tiles[i][j+1] = MovingRock
+              if i == 0 || chamber.tiles[i-1][j+1] == StoppedRock {
+                moving = false
+              }
+            } else {
+              if i == 0 || chamber.tiles[i-1][j] == StoppedRock {
+                moving = false
+              }
+            }
+          }
+        }
+      } else if jet == RightToLeft {
+        for j := 0; j < len(chamber.tiles[i]); j++ {
+          if chamber.tiles[i][j] == MovingRock {
+            if canShift {
+              chamber.tiles[i][j] = Empty
+              chamber.tiles[i][j-1] = MovingRock
+              if i == 0 || chamber.tiles[i-1][j-1] == StoppedRock {
+                moving = false
+              }
+            } else {
+              if i == 0 || chamber.tiles[i-1][j] == StoppedRock {
+                moving = false
+              }
+            }
+          }
+        }  
+      }
+    }
+
+    for i := lowestPoint; i < len(chamber.tiles); i++ {
+      for j := 0; j < len(chamber.tiles[i]); j++ {
+        if chamber.tiles[i][j] == MovingRock {
+          if moving {
+            chamber.tiles[i][j] = Empty
+            chamber.tiles[i-1][j] = MovingRock
+          } else {
+            chamber.tiles[i][j] = StoppedRock
+            if i > currHighestPoint {
+              currHighestPoint = i
+            }
+          }
+        }
+      }
+    }
+  }
+
+  if chamber.nRocks > len(chamber.jets) {
+    if _, ok := chamber.cache[newRock]; !ok {
+      chamber.cache[newRock] = make(map[int]PreviousAction)
+    }
+    chamber.cache[newRock][startJet] = PreviousAction{chamber.currentJet, currHighestPoint - chamber.highestPoint}
+  }
+  chamber.highestPoint = currHighestPoint + chamber.offset
+}
+
+func (chamber *Chamber) DropNRocks(nRocks int) {
+  var loopNewRock Rock
+  loopCurrentJet := -1
+  loopEndJet := -1
+  loopNRocks := 0
+  loopHeightDifference := 0
+  loopFound := false
+
+  var i int
+  for i = 0; i < nRocks && !loopFound; i++ {
+    newRock := GetRock(chamber.nRocks % 5)
+    found := false
+    if jets, ok := chamber.cache[newRock]; ok {
+      if result, ok := jets[chamber.currentJet]; ok {
+        if loopCurrentJet < 0 {
+          loopCurrentJet = chamber.currentJet
+          loopNewRock = newRock
+        }
+        if loopNRocks > 0 && loopNewRock == newRock && loopCurrentJet == chamber.currentJet {
+          loopFound = true
+        } else {
+          loopNRocks++
+          loopHeightDifference += result.heightDifference
+          loopEndJet = result.endJet
+          chamber.nRocks++
+          chamber.offset += result.heightDifference
+          chamber.highestPoint += result.heightDifference
+          chamber.currentJet = result.endJet
+        }
+        found = true
+      }
+    }
+    if !found {
+      chamber.DropRock()
+    }
+  }
+
+  if loopFound {
+    quotientRocks := int((nRocks - i) / loopNRocks)
+    chamber.nRocks += quotientRocks * loopNRocks
+    chamber.highestPoint += quotientRocks * loopHeightDifference
+    chamber.offset += quotientRocks * loopHeightDifference
+    chamber.currentJet = loopEndJet
+    i += quotientRocks * loopNRocks
+
+    for ; i <= nRocks; i++ {
+      chamber.DropRock()
+    }
+  }
+}
+
+func (chamber *Chamber) GetHighestPoint() int {
+  return chamber.highestPoint + 1
+}
+
+func (chamber *Chamber) Print() {
+  for i := len(chamber.tiles) - 1; i >= 0; i-- {
+    fmt.Print("|")
+    for j := 0; j < len(chamber.tiles[i]); j++ {
+      switch chamber.tiles[i][j] {
+        case Empty:
+          fmt.Print(".")
+        case MovingRock:
+          fmt.Print("@")
+        case StoppedRock:
+          fmt.Print("#")
+      }
+    }
+    fmt.Println("|")
+  }
+  fmt.Println("+-------+")
+}
+
+
+type Jet byte
+
+const (
+  LeftToRight Jet = iota
+  RightToLeft
+)
+
+
+func Parse(scanner bufio.Scanner) Chamber {
+  jets := []Jet{}
+
+  scanner.Scan()
+  line := scanner.Text()
+  for _, c := range(line) {
+    if c == '>' {
+      jets = append(jets, LeftToRight)
+    } else if c == '<' {
+      jets = append(jets, RightToLeft)
+    }
+  }
+
+  return *NewChamber(jets)
+}