Solve 2021 day 7-11

2021/d10.py

@@ -0,0 +1,63 @@
+from lib import get_data
+
+data = get_data(__file__).strip()
+
+OPEN = "([{<"
+CLOSE = ")]}>"
+
+
+def part1(line):
+    score = {
+        ")": 3,
+        "]": 57,
+        "}": 1197,
+        ">": 25137,
+    }
+    stack = []
+    for c in line:
+        if c in OPEN:
+            stack.append(OPEN.index(c))
+        elif c in CLOSE:
+            ci = CLOSE.index(c)
+            if stack and stack[-1] == ci:
+                stack.pop()
+                continue
+            else:
+                return score[c]
+        else:
+            assert False
+    return 0
+
+
+def part2(line):
+    stack = []
+    for c in line:
+        if c in OPEN:
+            stack.append(OPEN.index(c))
+        elif c in CLOSE:
+            ci = CLOSE.index(c)
+            if stack and stack[-1] == ci:
+                stack.pop()
+                continue
+            else:
+                assert False
+        else:
+            assert False
+    score = 0
+    for v in reversed(stack):
+        score *= 5
+        score += v + 1
+    return score
+
+
+s1 = 0
+s2s = []
+for line in data.splitlines():
+    s = part1(line)
+    if s == 0:
+        s2s.append(part2(line))
+    s1 += s
+
+print(s1)
+s2 = sorted(s2s)[len(s2s) // 2]
+print(s2)

2021/d11.py

@@ -0,0 +1,37 @@
+from lib import get_data
+from lib import Grid2D
+
+data = get_data(__file__).strip()
+g = Grid2D(data)
+
+flashes_100 = 0
+all_flash_round = None
+for i in range(10**9):
+    for row in range(g.n_rows):
+        for col in range(g.n_cols):
+            g[(row, col)] = str(int(g[(row, col)]) + 1)
+
+    has_flashed = set()
+    more_flashes = True
+    while more_flashes:
+        more_flashes = False
+        for row in range(g.n_rows):
+            for col in range(g.n_cols):
+                level = int(g[(row, col)])
+                if level > 9 and (row, col) not in has_flashed:
+                    more_flashes = True
+                    for nb in g.neighbors_adj((row, col)):
+                        g[nb] = str(int(g[nb]) + 1)
+                    has_flashed.add((row, col))
+    for oct in has_flashed:
+        g[oct] = "0"
+
+    if i < 100:
+        flashes_100 += len(has_flashed)
+
+    if len(has_flashed) == g.n_rows * g.n_cols:
+        all_flash_round = i + 1
+        break
+
+print(flashes_100)
+print(all_flash_round)

2021/d6.py

@@ -0,0 +1,32 @@
+from lib import get_data
+from lib import ints
+from collections import defaultdict
+
+data = get_data(__file__).strip()
+xs = ints(data)
+
+for _ in range(80):
+    for i in range(len(xs)):
+        if xs[i] == 0:
+            xs[i] = 6
+            xs.append(8)
+        else:
+            xs[i] -= 1
+
+print(len(xs))
+
+xs = ints(data)
+fish = defaultdict(int)
+for x in xs:
+    fish[x] += 1
+
+for _ in range(256):
+    new_fish = defaultdict(int)
+    new_fish[8] = fish[0]
+    new_fish[6] = fish[0]
+    for i in range(1, 9):
+        new_fish[i - 1] += fish[i]
+    fish = new_fish
+
+r = sum(fish.values())
+print(r)

2021/d7.py

@@ -0,0 +1,20 @@
+from lib import get_data
+from lib import ints
+
+data = get_data(__file__).strip()
+xs = ints(data)
+
+
+def d(t, x):
+    n = abs(t - x)
+    return n * (n + 1) // 2
+
+
+s_min_1 = 10**16
+s_min_2 = 10**16
+for t in range(min(xs), max(xs) + 1):
+    s_min_1 = min(s_min_1, sum(abs(t - x) for x in xs))
+    s_min_2 = min(s_min_2, sum(d(t, x) for x in xs))
+
+print(s_min_1)
+print(s_min_2)

2021/d8.py

@@ -0,0 +1,65 @@
+from lib import get_data
+from itertools import permutations
+
+data = get_data(__file__).strip()
+
+code_to_num = {
+    "cf": 1,
+    "acf": 7,
+    "bcdf": 4,
+    "acdeg": 2,
+    "acdfg": 3,
+    "abdfg": 5,
+    "abcefg": 0,
+    "abdefg": 6,
+    "abcdfg": 9,
+    "abcdefg": 8,
+}
+
+
+def translate(inn, mapping):
+    out = ""
+    for c in inn:
+        out += mapping[c]
+    return "".join(sorted(out))
+
+
+def decode(inn, out):
+    s = "abcdefg"
+    m = None
+    for p in permutations(s):
+        m = {k: v for k, v in zip(p, s)}
+        all = set(code_to_num.keys())
+        for in_code in inn:
+            out_code = translate(in_code, m)
+            if out_code in all:
+                all.remove(out_code)
+
+        if len(all) == 0:
+            break
+        else:
+            m = None
+
+    assert m is not None
+
+    o = 0
+    d = 1000
+    for out_code in out:
+        out_code = translate(out_code, m)
+        v = code_to_num[out_code]
+        o += d * v
+        d //= 10
+    return o
+
+
+s1 = 0
+s2 = 0
+for line in data.splitlines():
+    inn, out = line.strip().split(" | ")
+    inn = inn.split()
+    out = out.split()
+    s1 += sum(1 for v in out if len(v) in [2, 3, 4, 7])
+    s2 += decode(inn, out)
+
+print(s1)
+print(s2)

2021/d9.py

@@ -0,0 +1,47 @@
+from lib import get_data, Grid2D
+from collections import deque
+
+data = get_data(__file__).strip()
+g = Grid2D(data)
+
+s = 0
+low_points = []
+for row in range(g.n_rows):
+    for col in range(g.n_cols):
+        h = int(g[(row, col)])
+        for nb in g.neighbors_ort((row, col)):
+            if int(g[nb]) <= h:
+                break
+        else:
+            low_points.append((row, col))
+            s += 1 + h
+
+print(s)
+
+basins = []
+for row, col in low_points:
+    start = None
+    visited = set()
+    queue = deque([(row, col)])
+
+    while queue:
+        vertex = queue.popleft()
+        if vertex in visited:
+            continue
+        visited.add(vertex)
+
+        neighbors = []
+        for neighbor in g.neighbors_ort(vertex):
+            if neighbor in visited:
+                continue
+
+            neighbor_height = int(g[neighbor])
+            if neighbor_height < 9:
+                queue.append(neighbor)
+
+    basins.append(len(visited))
+
+s = 1
+for x in sorted(basins)[-3:]:
+    s *= x
+print(s)

README.md

@@ -172,12 +172,18 @@ Solutions and utility script for Advent of Code challenges in Python.
 
 ## AoC 2021
 
-- Day 1:  4:01   (Haha. Why am I so bad?!?!)
-- Day 2:  6:36   (Okay. I might as well stop doing these.)
-- Day 3: 23:46   (How long can I take when I try to take long?)
-- Day 4: 22:18   (No way. Such stupid bugs.)
-- Day 5: 13:30   (Decent, but obviously too slow.)
-- Day 6:
+- Day  1:  4:01   (Haha. Why am I so bad?!?!)
+- Day  2:  6:36   (Okay. I might as well stop doing these.)
+- Day  3: 23:46   (How long can I take when I try to take long?)
+- Day  4: 22:18   (No way. Such stupid bugs.)
+- Day  5: 13:30   (Decent, but obviously too slow.)
+- Day  6: 16:33   (Right idea quickly but then struggled to implement.)
+- Day  7:  6:12   (Decent, but too slow again, obviously. Maybe fast enough for part 1.)
+- Day  8: 72:00   (Yeah, that was too much of a struggle.)
+- Day  9:  8:07   (37th okay, okay)
+- Day 10: 15:50   (I was pretty happy with that but double the 100th place.)
+- Day 11: 11:43   (Could have been much faster here.)
+- Day 12:
 
 ## AoC 2022