part 12 day 2, inelegant

twelve.py

@@ -1,34 +1,30 @@
 #!/usr/bin/env python3
 from useful import *
-from igraph import *
 
 def parseline(s):
-    a, b = [x for x in s.strip().split('-')]
-    if b.isupper(): # ensure uppercase is never second
-        return (b, a)
-    return (a, b)
+    return [x for x in s.strip().split('-')]
 
-def uniqpath(a, b):
-    return '-'.join(sorted([a, b])) # ignore direction
-
-def solve(pos, matrix):
-    global pathname, index, visit
+def solve(pos, matrix, can_twice=False, path=[]):
+    global pathname, index, visit, cheat
     visit += 1
 
     if pathname[pos] == 'end':
+        pathtext = '-'.join([pathname[i] for i in (*path, pos)])
+        cheat |= {pathtext}
         return 1
 
     acc = 0
     if not pathname[pos].isupper():
         nextrix = matrix.copy()
-        for i in range(len(matrix)):
-            nextrix[i,pos] = False
-            nextrix[pos,i] = False
+        nextrix[:,pos] = False
+        nextrix[pos,:] = False
     else:
         nextrix = matrix
     for i in range(len(matrix)):
         if matrix[pos][i]:
-            acc += solve(i, nextrix)
+            acc += solve(i, nextrix, can_twice, path + [pos, ])
+            if can_twice and not pathname[pos].isupper() and pathname[pos] != 'start':
+                    acc += solve(i, matrix, False, path + [pos, ])
     return acc
 
 with open(0) as f:
@@ -50,5 +46,8 @@ with open(0) as f:
         matrix[index[a], index[b]] = True
         matrix[index[b], index[a]] = True
     ic(matrix)
+    cheat = set()
     print(solve(index['start'], matrix))
+    print(solve(index['start'], matrix, can_twice=True), '(may be duplicates)')
+    print(len(cheat))
     ic(visit)