Solution to problem 10 in Python

src/Year_2021/P10.py

@@ -99,5 +99,102 @@ def part_1() -> None:
     print(f"The total syntax error score is {res}")
 
 
+# --- Part Two ---
+
+# Now, discard the corrupted lines. The remaining lines are incomplete.
+
+# Incomplete lines don't have any incorrect characters - instead, they're
+# missing some closing characters at the end of the line. To repair the
+# navigation subsystem, you just need to figure out the sequence of closing
+# characters that complete all open chunks in the line.
+
+# You can only use closing characters (), ], }, or >), and you must add them in
+# the correct order so that only legal pairs are formed and all chunks end up
+# closed.
+
+# In the example above, there are five incomplete lines:
+
+#     [({(<(())[]>[[{[]{<()<>> - Complete by adding }}]])})].
+#     [(()[<>])]({[<{<<[]>>( - Complete by adding )}>]}).
+#     (((({<>}<{<{<>}{[]{[]{} - Complete by adding }}>}>)))).
+#     {<[[]]>}<{[{[{[]{()[[[] - Complete by adding ]]}}]}]}>.
+#     <{([{{}}[<[[[<>{}]]]>[]] - Complete by adding ])}>.
+
+# Did you know that autocomplete tools also have contests? It's true! The score
+# is determined by considering the completion string character-by-character.
+# Start with a total score of 0. Then, for each character, multiply the total
+# score by 5 and then increase the total score by the point value given for the
+# character in the following table:
+
+#     ): 1 point.
+#     ]: 2 points.
+#     }: 3 points.
+#     >: 4 points.
+
+# So, the last completion string above - ])}> - would be scored as follows:
+
+#     Start with a total score of 0.
+#     Multiply the total score by 5 to get 0, then add the value of ] (2) to
+# get a new total score of 2.
+#     Multiply the total score by 5 to get 10, then add the value of ) (1) to
+# get a new total score of 11.
+#     Multiply the total score by 5 to get 55, then add the value of } (3) to
+# get a new total score of 58.
+#     Multiply the total score by 5 to get 290, then add the value of > (4) to
+# get a new total score of 294.
+
+# The five lines' completion strings have total scores as follows:
+
+#     }}]])})] - 288957 total points.
+#     )}>]}) - 5566 total points.
+#     }}>}>)))) - 1480781 total points.
+#     ]]}}]}]}> - 995444 total points.
+#     ])}> - 294 total points.
+
+# Autocomplete tools are an odd bunch: the winner is found by sorting all of
+# the scores and then taking the middle score. (There will always be an odd
+# number of scores to consider.) In this example, the middle score is 288957
+# because there are the same number of scores smaller and larger than it.
+
+# Find the completion string for each incomplete line, score the completion
+# strings, and sort the scores. What is the middle score?
+
+
+def part_2() -> None:
+    _, scores = 0, []
+    for row in navigation_subsystem:
+        stack, score = [], 0
+        for char in row:
+            if char in chunks:
+                stack.append(chunks[char])
+            elif stack.pop() != char:
+                _ += points[char]
+                break
+        else:
+            for closing_char in reversed(stack):
+                score = score * 5 + " )]}>".index(closing_char)
+            scores.append(score)
+
+    res = sorted(scores)[len(scores) // 2]
+
+    print(f"The middle score is {res}")
+
+
+#   part1, part2 = 0, []
+#   for row in puzzle:
+#     stack, score = [], 0
+#     for c in row:
+#       if c in pairs:
+#         stack.append(pairs[c])
+#       elif stack.pop() != c:
+#         part1 += points[c]
+#         break
+#     else:
+#       for c in reversed(stack):
+#         score = score * 5 + ' )]}>'.index(c)
+#       part2.append(score)
+#   return part1, sorted(part2)[len(part2)//2]
+
 if __name__ == "__main__":
     part_1()
+    part_2()