Day 12

Author: foof

12/1.py

@@ -0,0 +1,41 @@
+
+from typing import List
+
+nodes = {}
+
+
+def find_path(current_node: str, destination: str, visited: List, paths: List):
+    if current_node != destination and current_node.islower() and current_node in visited:
+        return
+
+    visited = list(visited)
+    visited.append(current_node)
+
+    if current_node == destination:
+        paths.append(visited)
+        return
+
+    for next_node in nodes[current_node]:
+        find_path(next_node, destination, visited, paths)
+
+
+def solve():
+    paths = []
+    find_path('start', 'end', [], paths)
+    return len(paths)
+
+
+if __name__ == "__main__":
+    with open('./input', 'r') as f:
+        lines = f.read().splitlines()
+        for line in lines:
+            parent, child = line.split('-')
+            if parent not in nodes:
+                nodes[parent] = []
+            if child not in nodes:
+                nodes[child] = []
+            if child not in nodes[parent]:
+                nodes[parent].append(child)
+            if parent not in nodes[child]:
+                nodes[child].append(parent)
+        print(solve())

12/2.py

@@ -0,0 +1,44 @@
+
+from typing import List
+
+nodes = {}
+
+
+def find_path(current_node: str, destination: str, visited: List, paths: List):
+    if current_node == 'start' and len(visited) > 1:
+        return
+
+    if current_node.islower() and current_node in visited and max([visited.count(n) for n in visited if n.islower()]) > 1:
+        return
+
+    visited = list(visited)
+    visited.append(current_node)
+
+    if current_node == destination:
+        paths.append(visited)
+        return
+
+    for next_node in nodes[current_node]:
+        find_path(next_node, destination, visited, paths)
+
+
+def solve():
+    paths = []
+    find_path('start', 'end', [], paths)
+    return len(paths)
+
+
+if __name__ == "__main__":
+    with open('./input', 'r') as f:
+        lines = f.read().splitlines()
+        for line in lines:
+            parent, child = line.split('-')
+            if parent not in nodes:
+                nodes[parent] = []
+            if child not in nodes:
+                nodes[child] = []
+            if child not in nodes[parent]:
+                nodes[parent].append(child)
+            if parent not in nodes[child]:
+                nodes[child].append(parent)
+        print(solve())

12/input

@@ -0,0 +1,23 @@
+pn-TY
+rp-ka
+az-aw
+al-IV
+pn-co
+end-rp
+aw-TY
+rp-pn
+al-rp
+end-al
+IV-co
+end-TM
+co-TY
+TY-ka
+aw-pn
+aw-IV
+pn-IV
+IV-ka
+TM-rp
+aw-PD
+start-IV
+start-co
+start-pn