Graph Search: First working version & Shuffle problem

Graph-Search/cs412_bus_stops_a.py

@@ -8,14 +8,36 @@ Honor Code and Acknowledgments:
        Comments here on your code and submission.
 """
 
-from collections import deque
+from collections import defaultdict, deque
 
 
-def whatever_first_search(
+def whatever_first_search(graph: dict[str, set[str]], start: str, stop: str):
-    graph: dict[str, set[str]], start: str, stop: str
-) -> list[str]:
 
-    return []
+    bag: deque[tuple[str | None, str]] = deque()
+    bag.append((None, start))
+    visited: set[str] = set()
+    parent: dict[str, str | None] = {}
+
+    while len(bag) != 0:
+        parent_node, u = bag.pop()
+        if u in visited:
+            continue
+        visited.add(u)
+        parent[u] = parent_node
+
+        if u == stop:
+            path: list[str] = []
+            while u is not None:
+                path.append(u)
+                u = parent[u]
+            path.reverse()
+            return path
+
+        for v in graph[u]:
+            if v not in visited:
+                bag.append((u, v))
+
+    return None
 
 
 # All modules for CS 412 must include a main method that allows it
@@ -23,21 +45,18 @@ def whatever_first_search(
 def main():
     n: int = int(input())
 
-    graph: dict[str, set[str]] = {}
+    graph: dict[str, set[str]] = defaultdict(set)
 
     for _ in range(0, n):
         u, v = input().split()
-
-        if u not in graph:
-            graph[u] = set([v])
-        else:
         graph[u].add(v)
+        graph[v].add(u)
 
     target = input().split()
 
     path = whatever_first_search(graph, target[0], target[1])
 
-    if len(path) == 0:
+    if path is None:
         print("no route possible")
     else:
         print(" ".join(path))

Shuffle/inputs/sample1.txt

@@ -0,0 +1,3 @@
+ACF
+BCF
+ABCCFF

Shuffle/inputs/sample2.txt

@@ -0,0 +1,3 @@
+ACF
+BCF
+ABFCCF

Shuffle/shuffle.py

@@ -0,0 +1,54 @@
+"""
+name: Nicholas Tamassia
+
+Honor Code and Acknowledgments:
+
+        This work complies with the JMU Honor Code.
+
+       Comments here on your code and submission.
+"""
+
+
+def valid_shuffle(a: str, b: str, c: str) -> bool:
+
+    memo: list[list[bool | None]] = [
+        ([None] * (len(a) + 1)) for _ in range(0, len(b) + 1)
+    ]
+
+    memo[len(a)][len(b)] = True
+
+    def recurse(i: int, j: int) -> bool:
+        if i >= len(a) or j >= len(b):
+            return False
+
+        k: int = i + j
+        if k == (len(c) - 2):
+            return True
+
+        a_val: bool | None = memo[i + 1][j]
+        if a_val is None:
+            a_val = recurse(i + 1, j) if a[i] == c[k] else False
+
+        b_val: bool | None = memo[i][j + 1]
+        if b_val is None:
+            b_val = recurse(i, j + 1) if b[j] == c[k] else False
+
+        memo[i][j] = a_val or b_val
+
+        return a_val or b_val
+
+    return recurse(0, 0)
+
+
+# All modules for CS 412 must include a main method that allows it
+# to imported and invoked from other python scripts
+def main():
+    a: str = input()
+    b: str = input()
+    c: str = input()
+
+    print(valid_shuffle(a, b, c))
+
+
+if __name__ == "__main__":
+    main()