[py] Port 2018_04

py/aoc/__init__.py

@@ -2,7 +2,7 @@ import sys
 import argparse
 from pathlib import Path
 
-from .y2018 import d01, d02, d03
+from .y2018 import d01, d02, d03, d04
 from .y2020 import d10
 from .y2021 import d14
 from .y2022 import d01, d02, d03, d04, d05, d06
@@ -11,6 +11,7 @@ DAYS = {
     "2018_01": y2018.d01.solve,
     "2018_02": y2018.d02.solve,
     "2018_03": y2018.d03.solve,
+    "2018_04": y2018.d04.solve,
     "2020_10": y2020.d10.solve,
     "2021_14": y2021.d14.solve,
     "2022_01": y2022.d01.solve,

py/aoc/y2018/d04.py

@@ -0,0 +1,116 @@
+import re
+
+# PART 1
+
+ACTION_RE = r"\[(\d+)-(\d+)-(\d+) (\d+):(\d+)\] (.*)"
+GUARD_RE = r"Guard #(\d+) begins shift"
+
+
+def load_actions(inputstr):
+    actions = []
+    for line in inputstr.splitlines():
+        match = re.fullmatch(ACTION_RE, line)
+        y, m, d, hour, minute, action = match.groups()
+        y, m, d, hour, minute = int(y), int(m), int(d), int(hour), int(minute)
+        actions.append((y, m, d, hour, minute, action))
+    return actions
+
+
+def calculate_guards(actions):
+    guards = {}
+
+    guard = None
+    asleep_since = None
+
+    for action in sorted(actions):
+        _, _, _, _, m, text = action
+
+        match = re.fullmatch(GUARD_RE, text)
+        if match:
+            guard = int(match.group(1))
+
+        elif text == "falls asleep":
+            asleep_since = m
+
+        elif text == "wakes up":
+            l = guards.get(guard, [])
+            guards[guard] = l
+
+            l.append((asleep_since, m))
+
+    return guards
+
+
+def sleeps_longest(guards):
+    sleepiest_guard = None
+    sleepy_time = -1
+
+    for guard, sleep_times in guards.items():
+        total = 0
+        for start, end in sleep_times:
+            total += end - start
+
+        if total > sleepy_time:
+            sleepiest_guard = guard
+            sleepy_time = total
+
+    return sleepiest_guard
+
+
+def sleepiest_minute(times):
+    counter = {}
+    for start, end in times:
+        for m in range(start, end):
+            counter[m] = counter.get(m, 0) + 1
+
+    max_minute = None
+    amount = -1
+    for m, n in sorted(counter.items()):
+        if n > amount:
+            max_minute = m
+            amount = n
+
+    return max_minute
+
+
+# PART 2
+
+
+def sleep_times(times):
+    minutes = {}
+    for start, end in times:
+        for m in range(start, end):
+            minutes[m] = minutes.get(m, 0) + 1
+    return minutes
+
+
+def sleepy_minutes(guards):
+    minutes = {}
+    for guard, times in guards.items():
+        for m, n in sleep_times(times).items():
+            md = minutes.get(m, {})
+            minutes[m] = md
+            md[guard] = n
+
+    sleepy_minute = m
+    sleepy_guard = None
+    sleep_time = -1
+
+    for m, md in minutes.items():
+        for guard, n in md.items():
+            if n > sleep_time:
+                sleepy_minute = m
+                sleepy_guard = guard
+                sleep_time = n
+
+    return sleepy_guard, sleepy_minute
+
+
+def solve(inputstr):
+    actions = load_actions(inputstr)
+    guards = calculate_guards(actions)
+    guard = sleeps_longest(guards)
+    minute = sleepiest_minute(guards[guard])
+    print(f"Part 1: {guard * minute}")
+    guard_2, minute_2 = sleepy_minutes(guards)
+    print(f"Part 2: {guard_2 * minute_2}")