Recorded work from Monday.

graph-search/notes.md

@@ -133,8 +133,35 @@ How many moves does it take to reverse the string `123`?
 
 ## Recursive Depth-First Search (DFS)
 
-*   Worklist: …
+*   Worklist: Call Stack
 
              Activation Frames            Backpointers      Returned
     -----------------------------------   ------------ ------------------
-    edge = (⊥, a), incidence = …
+    edge = (⊥, a), incidence = (a, c)     a → (⊥, a)    [a, c, b, e, f, d]
+    edge = (a, c), incidence = (c, b)     c → (a, c)    [c, b, e, f, d]
+    edge = (c, b), incidence = (b, e)     b → (c, b)    [b, e, f, d]
+    edge = (b, a)                                       ⊥
+    edge = (b, e), incidence = (e, f)     e → (b, e)    [e, f, d]
+    edge = (e, f), incidence = (f, d)     f → (e, f)    [f, d]
+    edge = (f, d)                         d → (f, d)    [d]
+            ↑                                 ↑↑↑↑↑↑
+     Don't need this                     Don't need this
+
+For comparison, the iterative work has the same edges checked off as workitems, the same backpointers dictionary, and the same path:
+
+    Worklist    Backpointers
+    --------    ------------
+    (⊥, a) ✓    a → (⊥, a)
+    (a, c) ✓    c → (a, c)
+    (c, e)      b → (c, b)
+    (c, b) ✓    e → (b, e)
+    (b, e) ✓    f → (e, f)
+    (b, a) ✓    d → (f, d)
+    (e, d)
+    (e, f) ✓
+    (f, c)
+    (f, d) ✓
+
+    Reversed Path
+    ----
+    d ← f ← e ← b ← c ← a