days 4 and 5

2018/04.py

@@ -1,4 +1,4 @@
-from collections import defaultdict
+from collections import defaultdict, Counter
 from datetime import datetime
 import re
 
@@ -14,13 +14,44 @@ with open('data/04.txt') as f:
     events.sort(key=lambda e: e[0])
 
 
+spans = []
+sleep_start = None
+current_guard_id = None
+for dt, guard_id, event_type in events:
+    if event_type == 'begins shift':
+        current_guard_id = guard_id
+    elif event_type == 'falls asleep':
+        sleep_start = dt
+    elif event_type == 'wakes up':
+        spans.append((current_guard_id, sleep_start, dt))
+
 by_minute = defaultdict(lambda: defaultdict(list))
 by_guard = defaultdict(lambda: defaultdict(list))
-total_time_asleep = defaultdict(int)
+total_time_asleep = Counter()
+for guard_id, start, end in spans:
+    for i in range((end - start).seconds // 60):
+        minute = start.minute + i
+        by_minute[minute][guard_id].append(start.date())
+        by_guard[guard_id][minute].append(start.date())
+        total_time_asleep[guard_id] += 1
 
-current_guard_id = None
-spans = []
-for event in events:
-    dt, guard_id, event_type = event
-    if event_type = 'begins shift':
-        current_guard_id = guard_id
+sleepiest_guard = total_time_asleep.most_common()[0][0]
+sleepiest_minute, dates = sorted(
+    (m for m in by_guard[sleepiest_guard].items()), 
+    key=lambda x: len(x[1]), 
+    reverse=True
+)[0]
+
+print(f'Part 1: {sleepiest_guard * sleepiest_minute}\n')
+
+
+sleepiest_minute = defaultdict(lambda: (0, 0))
+for guard_id, minutes in by_guard.items():
+    for minute, dates in minutes.items():
+        times_asleep = len(dates)
+        if times_asleep > sleepiest_minute[minute][1]:
+            sleepiest_minute[minute] = (guard_id, times_asleep)
+
+minute, (guard_id, num_times_asleep) = sorted(sleepiest_minute.items(), key=lambda x: x[1][1], reverse=True)[0]
+
+print(f'Part 2: {minute * guard_id}\n')

2018/05.py

@@ -0,0 +1,43 @@
+from collections import Counter
+
+class Polymer:
+    def __init__(self, data, remove=None):
+        self.units = list(filter(lambda u: u.lower() != remove, data))
+        self.index = 0
+
+    def __len__(self):
+        return len(self.units)
+
+    def test(self, i):
+        try:
+            a, b = self.units[i], self.units[i + 1]
+        except IndexError:
+            return False
+        if a != b and a.lower() == b.lower():
+            return True
+        return False
+
+    def react(self):
+        while self.test(self.index):
+            del self.units[self.index:self.index + 2]
+            if self.index > 0:
+                self.index -= 1
+
+    def process(self):
+        while self.index < len(self) - 1:
+            self.react()
+            self.index += 1
+
+
+
+with open('data/05.txt') as f:
+    data = f.read().strip()
+
+
+results = []
+for unit_type in set(data.lower()):
+    p = Polymer(data, remove=unit_type)
+    p.process()
+    results.append(len(p))
+
+print(min(results))