seanhagen · December 20, 2019 02:35 · Dec 20, 2019
diff --git a/aoc2019-18-1.go b/aoc2019-18-1.go
@@ -0,0 +1,87 @@
+// this is the node thing for getting from the start position to the last key
+type path struct {
+  name     string
+  node     *tile
+  steps    int
+  parent   *path
+  children []path
+
+  keysFound []string
+
+  final bool
+
+  mapNow grid
+}
+
+// traverse takes a root node ( the '@' node ) and creates a graph
+// the graph won't be even or whatever the term is for each branch being the
+// same length because it'll stop adding nodes whenever there are no 'gettable'
+// keys left from where it ends up
+func traverse(in path) path {
+  if in.final {
+    return in
+  }
+
+  tmpGrid := in.mapNow.getCopy() /// make a copy
+  keys := tmpGrid.getableKeys(in.node)
+
+  // for all those keys
+  for _, k := range keys {
+    ng := tmpGrid.getCopy() /// do it again to be safe -- apparently messing up
+    // because when we do a second loop for [e d] it's not getting the right map
+    d := ng.tileToTileSteps(in.node, k)
+
+    kn := k.key
+    kf := []string{kn}
+    if len(in.keysFound) > 0 {
+      kf = append(kf, in.keysFound...)
+    }
+
+    ng2 := ng.removeKey(kn) // another copy
+    keysLeft := ng2.keys()
+    gettableKeys := ng2.getableKeys(k)
+
+    k.key = ""
+
+    np := path{
+      name:      kn,
+      node:      k,
+      parent:    &in,
+      steps:     in.steps + d,
+      children:  []path{},
+      mapNow:    ng2.getCopy(), // do it again again, to be super safe?
+      final:     len(keysLeft) <= 0,
+      keysFound: kf,
+    }
+
+    if len(keysLeft) > 0 && len(gettableKeys) > 0 {
+      np = traverse(np)
+    }
+
+    in.children = append(in.children, np)
+  }
+
+  return in
+}
+
+// should be creating a copy of the map/grid/whatever, but maybe isn't???
+func (g grid) getCopy() grid {
+  out := make(grid)
+  for n, t := range g {
+    nei := map[string]edge{}
+    for nn, e := range t.neighbours {
+      nei[nn] = e
+    }
+
+    nt := &tile{
+      id:         t.id,
+      key:        t.key,
+      door:       t.door,
+      coord:      t.coord,
+      neighbours: nei,
+    }
+
+    out[n] = nt
+  }
+  return out
+}