Solve a couple of 2017 problems.

2017/d10.py

@@ -0,0 +1,64 @@
+from lib import str_to_ints
+
+def part_1(data):
+    ns = list(range(256))
+    lenghts = str_to_ints(data)
+    i = 0
+    skip_size = 0
+
+    for length in lenghts:
+        a, b = i, (i + length) % len(ns)
+        if a <= b:
+            ns[a:b] = reversed(ns[a:b])
+        else:
+            rev = list(reversed(ns[a:] + ns[:b]))
+            ns[a:] = rev[:len(ns) - a]
+            ns[:b] = rev[-b:]
+        i = (i + length + skip_size) % len(ns)
+        skip_size += 1
+    print(ns[0] * ns[1])
+
+
+def part_2(data):
+    ns = list(range(256))
+    lenghts = list(map(ord, data)) + [17, 31, 73, 47, 23]
+    rounds = 64
+
+    i = 0
+    skip_size = 0
+    for _ in range(rounds):
+        for length in lenghts:
+            assert length < 256
+            a, b = i, (i + length) % len(ns)
+            if a <= b:
+                ns[a:b] = reversed(ns[a:b])
+            else:
+                rev = list(reversed(ns[a:] + ns[:b]))
+                ns[a:] = rev[:len(ns) - a]
+                if b != 0:
+                    ns[:b] = rev[-b:]
+            i = (i + length + skip_size) % len(ns)
+            assert len(ns) == 256
+            skip_size += 1
+
+    out = ""
+    for i in range(0, len(ns), 16):
+        r = 0
+        for j in range(i, i + 16):
+            r ^= ns[j]
+        out += f"{r:02x}"
+    return out
+
+
+def main():
+    data = open(0).read().strip()
+    part_1(data)
+    assert part_2("") == "a2582a3a0e66e6e86e3812dcb672a272"
+    assert part_2("AoC 2017") == "33efeb34ea91902bb2f59c9920caa6cd"
+    assert part_2("1,2,3") == "3efbe78a8d82f29979031a4aa0b16a9d"
+    assert part_2("1,2,4") =="63960835bcdc130f0b66d7ff4f6a5a8e"
+    print(part_2(data))
+
+
+if __name__ == "__main__":
+    main()

2017/d11.py

@@ -0,0 +1,52 @@
+from lib import add2
+from math import ceil
+
+
+DIR = {
+    "n": (-2, 0),
+    "s": (2, 0),
+    "e": (0, 1),
+    "w": (0, -1),
+    "ne": (-1, 1),
+    "nw": (-1, -1),
+    "se": (1, 1),
+    "sw": (1, -1),
+}
+
+
+def steps_to_zero(pos: tuple[int, int]):
+    c = list(map(abs, pos))
+    steps = c[1]
+    c[0] -= c[1]
+    if c[0] > 0:
+        steps += ceil(c[0] / 2)
+    return steps
+
+
+def part_1(data):
+    c = (0, 0)
+    for d in data.split(","):
+        c = add2(c, DIR[d])
+    return steps_to_zero(c)
+
+
+def part_2(data):
+    c = (0, 0)
+    steps_max = 0
+    for d in data.split(","):
+        c = add2(c, DIR[d])
+        steps_max = max(steps_to_zero(c), steps_max)
+    return steps_max
+
+
+def main():
+    data = open(0).read().strip()
+    print(part_1(data))
+    print(part_2(data))
+    assert part_1("ne,ne,ne") == 3
+    assert part_1("ne,ne,sw,sw") == 0
+    assert part_1("ne,ne,s,s") == 2
+    assert part_1("se,sw,se,sw,sw") == 3
+
+if __name__ == "__main__":
+    main()

2017/d12.py

@@ -0,0 +1,56 @@
+from lib import str_to_ints
+from collections import defaultdict
+
+
+def get_graph(data):
+    g = defaultdict(set)
+    for line in data.splitlines():
+        fs = str_to_ints(line)
+        l = fs[0]
+        for r in fs[1:]:
+            g[l].add(r)
+            g[r].add(l)
+    return g
+
+
+def part_1(data):
+    g = get_graph(data)
+    to_visit = [0]
+    seen = set()
+    while to_visit:
+        c = to_visit.pop()
+        if c in seen:
+            continue
+        seen.add(c)
+        for nb in g[c]:
+            to_visit.append(nb)
+    print(len(seen))
+
+
+def part_2(data):
+    g = get_graph(data)
+
+    group_count = 0
+    seen = set()
+    for c in g.keys():
+        if c in seen:
+            continue
+        group_count += 1
+        to_visit = [c]
+        while to_visit:
+            c = to_visit.pop()
+            if c in seen:
+                continue
+            seen.add(c)
+            for nb in g[c]:
+                to_visit.append(nb)
+    print(group_count)
+
+
+def main():
+    data = open(0).read().strip()
+    part_1(data)
+    part_2(data)
+
+if __name__ == "__main__":
+    main()

2017/d8.py

@@ -0,0 +1,28 @@
+from collections import defaultdict
+
+
+def part_1(data):
+    regs = defaultdict(int)
+    allmax = 0
+    for line in data.splitlines():
+        match line.split():
+            case [reg_a, op, value, "if", reg_c, cmp, val_c]:
+                value, val_c = int(value), int(val_c)
+                reg_val = regs[reg_c]
+                if eval(f"{reg_val} {cmp} {val_c}"):
+                    value = value if op == "inc" else -value
+                    regs[reg_a] += value
+            case _:
+                assert False
+        allmax = max(max(regs.values()), allmax)
+    print(max(regs.values()))
+    print(allmax)
+
+
+def main():
+    data = open(0).read().strip()
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()

2017/d9.py

@@ -0,0 +1,33 @@
+def part_1(data):
+    i = 0
+    group_score, garbage_score = 0, 0
+    in_garbage = False
+    group_level = 0
+    while i < len(data):
+        match data[i]:
+            case "{" if not in_garbage:
+                group_level += 1
+            case "}" if not in_garbage:
+                assert group_level > 0
+                group_score += group_level
+                group_level -= 1
+            case "<" if not in_garbage:
+                in_garbage = True
+            case ">" if in_garbage:
+                in_garbage = False
+            case "!" if in_garbage:
+                i += 1
+            case _ if in_garbage:
+                garbage_score += 1
+        i += 1
+    print(group_score)
+    print(garbage_score)
+
+
+def main():
+    data = open(0).read().strip()
+    part_1(data)
+
+
+if __name__ == "__main__":
+    main()

README.md

@@ -57,8 +57,7 @@ written in Python.
 - Day 22: 90:00
 - Day 23: 60:00
 - Day 24: 48:00
-- Day 25:
-
+- Day 25: 6:45
 
 # 2017
 
@@ -69,4 +68,9 @@ written in Python.
 - Day 5: 6:13
 - Day 6: 8:37
 - Day 7: 19:22
-- Day 8: 
+- Day 8: 8:15
+- Day 9: 6:10
+- Day 10: 55:00
+- Day 11: 66:06
+- Day 12: 6:44
+- Day 13: