Start solving 2018 problems

I have also updated get.py to download the problems as
`d<day>.txt` instead of `i<day>.txt`. That allows me
to get the day input via `__input__.replace('.py', '.txt')`
which is a little more concise. I don't know why
I didn't do this earlier.

2018/d1.py

@@ -0,0 +1,28 @@
+def part_1(data):
+    r = 0
+    for x in data.splitlines():
+        r += int(x)
+    print(r)
+
+
+def part_2(data):
+    seen = set()
+    r = 0
+    while True:
+        for x in data.splitlines():
+            r += int(x)
+            if r in seen:
+                print(r)
+                return
+            seen.add(r)
+
+
+def main():
+    with open("i1.txt") as f:
+        data = f.read()
+    part_1(data)
+    part_2(data)
+
+
+if __name__ == "__main__":
+    main()

2018/d2.py

@@ -0,0 +1,53 @@
+from lib import LETTERS_LOWER
+
+
+def part_1(data):
+    two_count, three_count = 0, 0
+    for line in data.splitlines():
+        count = [line.count(c) for c in LETTERS_LOWER if line.count(c) > 1]
+        if 2 in count:
+            two_count += 1
+        if 3 in count:
+            three_count += 1
+    r = two_count * three_count
+    print(r)
+
+
+def equal(a, b):
+    c = 0
+    if len(a) != len(b):
+        return False
+    for i in range(len(a)):
+        if a[i] != b[i]:
+            c += 1
+    if c == 1:
+        return True
+    return False
+
+
+def strip(a, b):
+    r = ""
+    for a, b in zip(a, b):
+        if a == b:
+            r += a
+    return r
+
+
+def part_2(data):
+    lines = list(data.splitlines())
+    for i in range(len(lines)):
+        for j in range(i + 1, len(lines)):
+            a, b = lines[i], lines[j]
+            if equal(a, b):
+                print(strip(a, b))
+
+
+def main():
+    with open("i2.txt") as f:
+        data = f.read()
+    part_1(data)
+    part_2(data)
+
+
+if __name__ == "__main__":
+    main()

2018/d3.py

@@ -0,0 +1,44 @@
+from lib import str_to_ints
+from collections import defaultdict
+
+
+def part_1(data):
+    claims = defaultdict(int)
+    for line in data.splitlines():
+        id, x, y, w, h = str_to_ints(line)
+        for dx in range(w):
+            for dy in range(h):
+                claims[(x + dx, y + dy)] += 1
+
+    r = sum([1 for v in claims.values() if v > 1])
+    print(r)
+
+
+def part_2(data):
+    claims = defaultdict(list)
+    all_ids = set()
+    for line in data.splitlines():
+        id, x, y, w, h = str_to_ints(line)
+        for dx in range(w):
+            for dy in range(h):
+                claims[(x + dx, y + dy)].append(id)
+        all_ids.add(id)
+
+    for xs in claims.values():
+        if len(xs) > 1:
+            for x in xs:
+                if x in all_ids:
+                    all_ids.remove(x)
+    assert len(all_ids) == 1
+    print(all_ids.pop())
+
+
+def main():
+    with open("i3.txt") as f:
+        data = f.read()
+    part_1(data)
+    part_2(data)
+
+
+if __name__ == "__main__":
+    main()

2018/d4.py

@@ -0,0 +1,67 @@
+from lib import str_to_ints
+from collections import defaultdict
+
+
+def part_1(data):
+    shifts = sorted(data.splitlines())
+    guards = defaultdict(list)
+    guard = None
+    for s in shifts:
+        try:
+            _, _, _, h, m, guard = str_to_ints(s)
+        except ValueError:
+            _, _, _, h, m = str_to_ints(s)
+            assert guard is not None
+            guards[guard].append((h, m))
+
+    guard_sleep_times = {}
+    guard_heat_maps = {}
+    for guard, times in guards.items():
+        heat_map = [0 for _ in range(60)]
+        total_time = 0
+        start = None
+        for h, m in times:
+            if start is None:
+                start = (h, m)
+            else:
+                delta = (h - start[0]) * 60 + (m - start[1])
+                total_time += delta
+                for t in range(start[1], m):
+                    heat_map[t] += 1
+                start = None
+        guard_sleep_times[guard] = total_time
+        guard_heat_maps[guard] = heat_map
+
+    max_guard, max_time = None, 0
+    for guard, time in guard_sleep_times.items():
+        if time > max_time:
+            max_guard = guard
+            max_time = time
+
+    assert type(max_guard) is int
+    max_minute, max_asleep = 0, 0
+    for minute, asleep in enumerate(guard_heat_maps[max_guard]):
+        if asleep > max_asleep:
+            max_minute = minute
+            max_asleep = asleep
+    print(max_guard * max_minute)
+
+    max_guard, max_minute, max_asleep = 0, 0, 0
+    for guard in guard_sleep_times.keys():
+        for minute, asleep in enumerate(guard_heat_maps[guard]):
+            if asleep > max_asleep:
+                max_minute = minute
+                max_asleep = asleep
+                max_guard = guard
+    print(max_guard * max_minute)
+
+
+def main():
+    input_file = __file__.replace(".py", ".txt")
+    with open(input_file) as f:
+        data = f.read()
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()

2018/lib.py

@@ -0,0 +1 @@
+../lib.py

README.md

@@ -86,3 +86,11 @@ written in Python.
 - Day 23: Multiple days... but super fun.
 - Day 24: 15:45 (48th)
 - Day 25: 41:00
+
+# 2018
+
+- Day 1: 1:49
+- Day 2: 10:53
+- Day 3: 6:16
+- Day 4: 25:16
+- Day 5:

get.py

@@ -12,12 +12,14 @@ year = sys.argv[1]
 day = sys.argv[2]
 
 session_cookie = get_password('aoc-session-cookie', 'felixm')
+assert session_cookie is not None
+
 url = f"https://adventofcode.com/{year}/day/{day}/input"
 cookies = {'session': session_cookie}
 response = requests.get(url, cookies=cookies)
 
 if response.status_code == 200:
-    filename = f"i{day}.txt"
+    filename = f"d{day}.txt"
     with open(filename, 'w') as file:
         file.write(response.text)
     print(f"Year {year} {filename} written.")