2023/gareth/utils/sparseGrid/sparseGrid.go

   1 package sparsegrid
   2
   3 import (
   4         "fmt"
   5         "strings"
   6
   7         "adventofcode2022/utils"
   8 )
   9
  10 type SparseGrid[T comparable] struct {
  11         minX, maxX, minY, maxY int
  12         data                   map[string]T
  13         empty                  T
  14 }
  15
  16 func NewGrid[T comparable](empty T) *SparseGrid[T] {
  17         return &SparseGrid[T]{
  18                 minX:  utils.MaxInt,
  19                 maxX:  utils.MinInt,
  20                 minY:  utils.MaxInt,
  21                 maxY:  utils.MinInt,
  22                 data:  map[string]T{},
  23                 empty: empty,
  24         }
  25 }
  26
  27 func (g *SparseGrid[T]) SizeX() (int, int) {
  28         return g.minX, g.maxX
  29 }
  30
  31 func (g *SparseGrid[T]) SizeY() (int, int) {
  32         return g.minY, g.maxY
  33 }
  34
  35 func (g *SparseGrid[T]) Visited() int {
  36         return len(g.data)
  37 }
  38
  39 func (g *SparseGrid[T]) Get(x, y int) T {
  40         k := key(x, y)
  41         v, ok := g.data[k]
  42         if !ok {
  43                 return g.empty
  44         }
  45         return v
  46 }
  47
  48 func (g *SparseGrid[T]) Set(x, y int, v T) {
  49         k := key(x, y)
  50         current, ok := g.data[k]
  51         if ok && v == current {
  52                 return
  53         } else if !ok && v == g.empty {
  54                 return
  55         } else if v == g.empty {
  56                 delete(g.data, k)
  57         } else {
  58                 g.data[k] = v
  59                 g.minX = utils.Min(g.minX, x)
  60                 g.maxX = utils.Max(g.maxX, x)
  61                 g.minY = utils.Min(g.minY, y)
  62                 g.maxY = utils.Max(g.maxY, y)
  63         }
  64 }
  65
  66 func (g *SparseGrid[T]) StringWithFormatter(formatter func(T, int, int) string) string {
  67         var r strings.Builder
  68         for j := g.minY; j <= g.maxY; j++ {
  69                 for i := g.minX; i <= g.maxX; i++ {
  70                         _, err := r.WriteString(formatter(g.Get(i, j), i, j))
  71                         utils.PanicOnErr(err)
  72                 }
  73                 _, err := r.WriteRune('\n')
  74                 utils.PanicOnErr(err)
  75         }
  76         return r.String()
  77 }
  78
  79 func key(x, y int) string {
  80         return fmt.Sprintf("%d:%d", x, y)
  81 }