another coding evening

04/solve01.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python
+from datetime import datetime
+import re
+
+RE_BEGIN = re.compile("^\[(.*)\] Guard #(\d+) begins shift$")
+RE_SLEEP = re.compile("^\[(.*)\] falls asleep$")
+RE_AWAKE = re.compile("^\[(.*)\] wakes up$")
+
+guards = dict()
+
+def read_input():
+    with open('input.txt', 'r') as f:
+        data = f.read().splitlines()
+        return sorted(data)
+
+def convert_time(data):
+    return datetime.strptime(data, '%Y-%m-%d %H:%M')
+
+def guard_stop_shift(guard, date):
+    guard_awake(guard, date)
+
+def guard_start_shift(guard, date):
+    if guard is None:
+        return
+    if guard not in guards:
+        guards[guard] = {
+            'guard': guard,
+            'state': 'awake',
+            'min': [0]*60,
+            'sleep': 0,
+            'last_time': None
+        }
+    guard_awake(guard, date)
+
+def guard_sleep(guard, date):
+    if guard is None:
+        return
+    guards[guard]['state'] = 'sleep'
+    guards[guard]['last_time'] = date
+
+def guard_awake(guard, date):
+    if guard is None:
+        return
+    if guards[guard]['state'] in ['awake']:
+        guards[guard]['last_time'] = date
+        return
+
+    m = int((date - guards[guard]['last_time']).total_seconds() / 60)
+    m1 = guards[guard]['last_time'].minute
+    for x in range(m):
+        m2 = (x + m1) % 60
+        guards[guard]['min'][m2] += 1
+    guards[guard]['sleep'] += m
+    guards[guard]['state'] = 'awake'
+    guards[guard]['last_time'] = date
+
+
+current_guard = None
+for line in read_input():
+    m = RE_BEGIN.match(line)
+    if m:
+        d = convert_time(m.group(1))
+        guard_stop_shift(current_guard, d)
+        current_guard = (int)(m.group(2))
+        guard_start_shift(current_guard, d)
+        continue
+
+    m = RE_SLEEP.match(line)
+    if m:
+        d = convert_time(m.group(1))
+        guard_sleep(current_guard, d)
+        continue
+
+    m = RE_AWAKE.match(line)
+    if m:
+        d = convert_time(m.group(1))
+        guard_awake(current_guard, d)
+        continue
+
+    print(line)
+    raise Exception('unpasable line')
+
+max_sleep = max(guards.values(), key=lambda i: i['sleep'])
+max_min  = max(max_sleep['min'])
+max_min_pos = [i for i, j in enumerate(max_sleep['min']) if j == max_min]
+
+print(max_sleep['guard'] * max_min_pos[0])