2018 Day 15 Completed!

2018/day15/map.go

@@ -0,0 +1,49 @@
+package main
+
+type Coordinate struct {
+	X, Y int
+}
+
+var offsets = []Coordinate{
+	{0, -1},
+	{-1, 0},
+	{1, 0},
+	{0, 1},
+}
+
+type Map map[int]map[int]*Tile
+
+func (m Map) SetTile(t *Tile, x, y int) {
+	if m[y] == nil {
+		m[y] = make(map[int]*Tile)
+	}
+	m[y][x] = t
+	t.X = x
+	t.Y = y
+	t.Map = m
+}
+
+func (m Map) Tile(x, y int) *Tile {
+	if m[y] == nil {
+		return nil
+	}
+	return m[y][x]
+}
+
+func (m Map) FindWalkableTiles(t *Tile) (map[*Tile]int, map[*Tile]*Tile) {
+	frontier := []*Tile{t}
+	distance := map[*Tile]int{t: 0}
+	cameFrom := map[*Tile]*Tile{t: nil}
+	for len(frontier) > 0 {
+		current := frontier[0]
+		frontier = frontier[1:]
+		for _, next := range current.WalkableNeighbors() {
+			if _, ok := distance[next]; !ok {
+				frontier = append(frontier, next)
+				distance[next] = distance[current] + 1
+				cameFrom[next] = current
+			}
+		}
+	}
+	return distance, cameFrom
+}