Designed and implemented a recursive DFS.

graph-search/notes.md

@@ -134,8 +134,14 @@ In the weighted directed graph on the whiteboard, what is the shortest path from
 
 ## Recursive Depth-First Search (DFS)
 
-*   Worklist: …
+*   Worklist: Call Ctack (activation frames)
 
              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]

graph-search/src/features/search/search.js

@@ -131,6 +131,19 @@ export function bestFirst(graph, source, destination) {
   return undefined;
 }
 
-export function recursiveDFS(graph, source, destination) {
-  return undefined; // TODO: stub
+export function recursiveDFS(graph, source, destination, visited = new Set()) {
+  if (visited.has(source)) {
+    return undefined;
+  }
+  visited.add(source);
+  if (source === destination) {
+    return [source];
+  }
+  for (const incidence of graph.getIncidences(source)) {
+    const suffix = recursiveDFS(graph, incidence.destination, destination, visited);
+    if (suffix !== undefined) {
+      return [source, ...suffix];
+    }
+  }
+  return undefined;
 }

graph-search/src/features/search/solution.js

@@ -29,7 +29,7 @@ function formatSolution(solution) {
 }
 
 export function Solution(props) {
-  const search = bestFirst;
+  const search = recursiveDFS;
   const firstSolution = search(firstExample, 'a', 'd');
   const secondSolution = search(secondExample, '123', '321');
   return (