2017 Day 9 Part 1

2017/day09.py

@@ -1,94 +1,46 @@
-import enum
+def part1(text):
+    return score(clean(text))
 
-@enum.unique
-class Token(enum.Enum):
-    GroupStart = '{'
-    GroupEnd = '}'
-    GarbageStart = '<'
-    GarbageEnd = '>'
-    Cancel = '!'
 
-def log(f):
-    def _(*args):
-        ret = f(*args)
-        print(*args, '->', ret)
-        return ret
-    return _
-
-def tokenize(stream):
-    tokens = {t.value: t for t in Token}
-    return [tokens[c] for c in stream if c in tokens]
-
-def cancel(tokens):
-    stack = []
+def clean(text: str) -> str:
+    out = ""
     i = 0
-    cancellations = 0
-    while i < len(tokens):
-        t = tokens[i]
-        if t == Token.Cancel:
-            cancellations += 1
+    garbage = False
+    while i < len(text):
+        c = text[i]
+        if c == "!":
             i += 2
             continue
-        stack.append(t)
+
+        if garbage and c == ">":
+            garbage = False
+        elif garbage:
+            pass
+        elif c == "<":
+            garbage = True
+        else:
+            out += c
         i += 1
 
-    assert len(tokens) == len(stack) + 2*cancellations
+    assert not garbage, "All garbage must be closed"
+    return out
 
-    return stack
 
-def clean(tokens):
-    stack = []
-    i = 0
-    while i < len(tokens):
-        if tokens[i] == Token.GarbageStart:
-            while tokens[i] != Token.GarbageEnd:
-                i += 1
-            i += 1
-            continue
-        print('PUSH:', i, tokens[i])
-        stack.append(tokens[i])
-        i += 1
-    return stack
+def score(text: str) -> int:
+    depth = 0
+    points = 0
+    for c in text:
+        if c == "{":
+            depth += 1
+        if c == "}":
+            points += depth
+            depth -= 1
 
-class Group:
-    def __init__(self):
-        self.children = []
+    assert depth == 0, "All groups must be closed"
+    return points
 
-    def append(self, child):
-        self.children.append(child)
 
-    def __repr__(self):
-        return '{{}}'.format(''.join(repr(c) for c in self.children))
-
-    __str__ = __repr__
-
-def parse(tokens):
-    stack = []
-    outer = Group()
-    last = None
-    tokens = list(clean(cancel(tokens)))
-    print(len([t for t in tokens if t == Token.GroupStart]), len([t for t in tokens if t == Token.GroupEnd]))
-    assert len([t for t in tokens if t == Token.GroupStart]) == len([t for t in tokens if t == Token.GroupEnd])
-    for t in tokens:
-        if t == Token.GroupStart:
-            g = Group()
-            if stack:
-                stack[-1].append(g)
-            stack.append(g)
-        elif t == Token.GroupEnd:
-            last = stack.pop(-1)
-    return last
-
-def score(group, depth=1):
-    return depth + sum(score(c, depth+1) for c in group.children)
-
-def solve(stream):
-    stuff = parse(tokenize(stream))
-    if stuff is None: return 0
-    return score(stuff)
-
-with open('input/day9') as f:
+with open("input/day09.txt") as f:
     puzzle_input = f.read()
 
-#  print(solve('<{o"i!a,<{i<a>'))
-print(solve(puzzle_input))
+print(part1(puzzle_input))