Big update: Adding all advent of codes to same repo

AdventOfCode2020/day24/day24.go

@@ -0,0 +1,178 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type Hex struct {
+  q int
+  r int
+  s int
+}
+
+func CreateHex(q int, r int, s int) Hex {
+  return Hex{
+    q: q,
+    r: r,
+    s: s,
+  }
+}
+
+func (h *Hex) Print() string {
+  return strconv.Itoa(h.q) + "," + strconv.Itoa(h.r) + "," + strconv.Itoa(h.s)
+}
+
+func Count(arr []string, search string) int {
+  counter := 0
+  for i := 0; i < len(arr); i++ {
+    if arr[i] == search {
+      counter++
+    }
+  }
+  return counter
+}
+
+func AdjustValues(hexMap map[string]bool, key string, white *int, black *int) {
+  v, exists := hexMap[key]
+  if !exists {
+    return
+  }
+
+  if v {
+    *white++
+  } else {
+    *black++
+  }
+}
+
+func AddIfMissing(hexMap map[string]bool, hex string) {
+  _, exists := hexMap[hex]
+  if !exists {
+    hexMap[hex] = true
+  }
+}
+
+func AddAdjacents(hexMap map[string]bool, hex string) {
+  split := strings.Split(hex, ",")
+  q, _ := strconv.Atoi(split[0])
+  r, _ := strconv.Atoi(split[1])
+  s, _ := strconv.Atoi(split[2])
+
+  nw := strconv.Itoa(q) + "," + strconv.Itoa(r - 1) + "," + strconv.Itoa(s + 1)
+  w := strconv.Itoa(q - 1) + "," + strconv.Itoa(r) + "," + strconv.Itoa(s + 1)
+  sw := strconv.Itoa(q - 1) + "," + strconv.Itoa(r + 1) + "," + strconv.Itoa(s)
+  se := strconv.Itoa(q) + "," + strconv.Itoa(r + 1) + "," + strconv.Itoa(s - 1)
+  e := strconv.Itoa(q + 1) + "," + strconv.Itoa(r) + "," + strconv.Itoa(s - 1)
+  ne := strconv.Itoa(q + 1) + "," + strconv.Itoa(r - 1) + "," + strconv.Itoa(s)
+
+  AddIfMissing(hexMap, nw)
+  AddIfMissing(hexMap, w)
+  AddIfMissing(hexMap, sw)
+  AddIfMissing(hexMap, se)
+  AddIfMissing(hexMap, e)
+  AddIfMissing(hexMap, ne)
+}
+
+func CountAdjacent(hexMap map[string]bool, hex string) (int, int) {
+  white := 0
+  black := 0
+
+  split := strings.Split(hex, ",")
+  q, _ := strconv.Atoi(split[0])
+  r, _ := strconv.Atoi(split[1])
+  s, _ := strconv.Atoi(split[2])
+
+  nw := strconv.Itoa(q) + "," + strconv.Itoa(r - 1) + "," + strconv.Itoa(s + 1)
+  w := strconv.Itoa(q - 1) + "," + strconv.Itoa(r) + "," + strconv.Itoa(s + 1)
+  sw := strconv.Itoa(q - 1) + "," + strconv.Itoa(r + 1) + "," + strconv.Itoa(s)
+  se := strconv.Itoa(q) + "," + strconv.Itoa(r + 1) + "," + strconv.Itoa(s - 1)
+  e := strconv.Itoa(q + 1) + "," + strconv.Itoa(r) + "," + strconv.Itoa(s - 1)
+  ne := strconv.Itoa(q + 1) + "," + strconv.Itoa(r - 1) + "," + strconv.Itoa(s)
+
+  AdjustValues(hexMap, nw, &white, &black)
+  AdjustValues(hexMap, w, &white, &black)
+  AdjustValues(hexMap, sw, &white, &black)
+  AdjustValues(hexMap, se, &white, &black)
+  AdjustValues(hexMap, e, &white, &black)
+  AdjustValues(hexMap, ne, &white, &black)
+
+  return white, black
+}
+
+func main() {
+  fmt.Println("Day 24 Part 1")
+
+  file, err := os.ReadFile("input.txt")
+  if err != nil {
+    panic(err)
+  }
+  _content := strings.Split(string(file), "\n")
+  content := _content[:len(_content) - 1]
+
+  directionRegex := regexp.MustCompile("e|se|sw|w|nw|ne")
+
+  // true = white, false = black
+  cache := make(map[string]bool)
+
+  for _, line := range content {
+    matches := directionRegex.FindAllString(line, -1)
+    
+    nw := Count(matches, "nw")
+    w := Count(matches, "w")
+    sw := Count(matches, "sw")
+    se := Count(matches, "se")
+    e := Count(matches, "e")
+    ne := Count(matches, "ne")
+
+    hex := CreateHex(ne + e - sw - w, se + sw - ne - nw, w + nw - se - e)
+
+    white, exists := cache[hex.Print()]
+    if !exists {
+      cache[hex.Print()] = false
+    } else {
+      cache[hex.Print()] = !white
+    }
+  }
+
+  blackTiles := 0
+  for _, white := range cache {
+    if !white {
+      blackTiles++
+    }
+  }
+
+  fmt.Printf("Part 1: %d\n", blackTiles)
+
+  for i := 0; i < 100; i++ {
+    
+    toFlip := make([]string, 0)
+    for k := range cache {
+      AddAdjacents(cache, k)
+    }
+
+    for k, isWhite := range cache {
+      _, black := CountAdjacent(cache, k)
+      if isWhite && black == 2 {
+        toFlip = append(toFlip, k) 
+      } else if !isWhite && (black == 0 || black > 2) {
+        toFlip = append(toFlip, k) 
+      }
+    }
+
+    for _, k := range toFlip {
+      cache[k] = !cache[k]
+    }
+
+    myTiles := 0
+    for _, white := range cache {
+      if !white {
+        myTiles++
+      }
+    }
+    fmt.Println(i, myTiles)
+  }
+}