13

13/13.py

@@ -0,0 +1,59 @@
+
+with open('input') as file:
+    packets = list(tuple(map(eval, x.split('\n'))) for x in file.read().strip().split('\n\n'))
+
+
+def is_int(x):
+    return isinstance(x, int)
+def is_list(x):
+    return isinstance(x, list)
+
+def compare_packets(l, r):
+    def compare(left, right):
+        nonlocal result, done
+        if not done:
+            if is_int(left) and is_int(right):
+                if left>right:
+                    result = False
+                    done = True
+                elif left<right:
+                    result = True
+                    done = True
+            elif is_list(left) and is_list(right):
+                for l, r in zip(left, right):
+                    compare(l, r)
+                    if done:
+                        break
+                else:
+                    if len(right)<len(left):
+                        result = False
+                        done = True
+                    elif len(left)<len(right):
+                        result = True
+                        done = True
+            elif is_int(left):
+                compare([left], right)
+            else:
+                compare(left, [right])
+    result = None
+    done = False
+    compare(l, r)
+    return result
+
+print(sum(i for i, (l, r) in enumerate(packets, 1) if compare_packets(l, r)))
+packets = [x for y in packets for x in y] + [[[2]], [[6]]]
+
+for i in range(len(packets)):
+    for j in range(len(packets)-1):
+        if not compare_packets(packets[j], packets[j+1]):
+            packets[j], packets[j+1] = packets[j+1], packets[j]
+a = -1
+b = -1
+for i in range(len(packets)):
+    if packets[i]==[[2]]:
+        a = i+1
+    if packets[i]==[[6]]:
+        b = i+1
+print(a*b)
+
+