Add days 11,12,13,14, 2016

Author: snhansen

2016/day11/solution.py

@@ -0,0 +1,47 @@
+from itertools import combinations
+from collections import deque
+
+
+def bad_state(chips, generators):
+    for chip, gen in zip(chips, generators):
+        for other_gen in generators:
+            if gen == other_gen:
+                continue
+            if chip == other_gen and chip != gen:
+                return True
+    return False
+
+
+def solve(chips, generators):
+    q = deque([(0, 1, chips, generators)])
+    seen = set()
+    while q:
+        steps, floor, chips, generators = q.popleft()
+        if (floor, chips, generators) in seen:
+            continue
+        seen.add((floor, chips, generators))
+        if all(chip == 4 for chip in chips) and all(gen == 4 for gen in generators):
+            return steps
+        # Purge wrong states: if any chip is at a floor with another generator but not its own generator, then we purge.
+        if bad_state(chips, generators):
+            continue
+        # Need to move one or two items to a floor above or below.
+        avail_items = [i for i, x in enumerate(chips) if x == floor]
+        avail_items += [i + len(chips) for i, x in enumerate(generators) if x == floor]
+        for new_floor in {floor - 1, floor + 1} & {1, 2, 3, 4}:
+            for items in combinations(avail_items + [None], 2):
+                new_chips = list(chips)
+                new_generators = list(generators)
+                for item in items:
+                    if item is not None:
+                        if item < len(chips):
+                            new_chips[item] = new_floor
+                        else:
+                            new_generators[item - len(chips)] = new_floor
+                q.append((steps + 1, new_floor, tuple(new_chips), tuple(new_generators)))
+
+# Part 1
+print(solve((1, 1, 3, 2, 2), (1, 1, 2, 2, 2)))
+
+# Part 2
+print(solve((1, 1, 3, 2, 2, 1, 1), (1, 1, 2, 2, 2, 1, 1)))

2016/day12/solution.py

@@ -0,0 +1,36 @@
+with open("input") as f:
+    inp = f.read().strip()
+
+instr = []
+for line in inp.split("\n"):
+    op, *rest = line.split(" ")
+    instr.append((op, rest))
+    
+
+def solve(c):
+    register = {x: 0 for x in ("a", "b", "c", "d")}
+    register["c"] = c
+    pointer = 0
+    while pointer < len(instr):
+        op, rest = instr[pointer]
+        if op == "cpy":
+            val, target = rest
+            register[target] = int(val) if val.isnumeric() else int(register[val])
+        elif op == "inc":
+            register[rest[0]] += 1
+        elif op == "dec":
+            register[rest[0]] -= 1
+        elif op == "jnz":
+            x, y = rest
+            decider = int(x) if x.isnumeric() else register[x]
+            if decider != 0:
+                pointer += int(y)
+                continue
+        pointer += 1
+    return register["a"]
+
+# Part 1
+print(solve(0))
+
+# Part 2
+print(solve(1))

2016/day13/solution.py

@@ -0,0 +1,46 @@
+from collections import deque
+
+
+def is_open(x, y):
+    res = x*x + 3*x + 2*x*y + y + y*y + 1364
+    return bin(res)[2:].count("1") % 2 == 0
+
+
+# Part 1
+sx, sy = 1, 1
+ex, ey = 31, 39
+seen = set()
+q = deque([(0, sx, sy)])
+while q:
+    steps, x, y = q.popleft()
+    if (x, y) == (ex, ey):
+        print(steps)
+        break
+    if (x, y) in seen:
+        continue
+    seen.add((x, y))
+    for dx, dy in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
+        nx = x + dx
+        ny = y + dy
+        if nx >= 0 and ny >= 0 and is_open(nx, ny):
+            q.append((steps + 1, nx, ny))
+
+
+# Part 2
+sx, sy = 1, 1
+seen = set()
+q = deque([(0, sx, sy)])
+while q:
+    steps, x, y = q.popleft()
+    if steps > 50:
+        continue
+    if (x, y) in seen:
+        continue
+    seen.add((x, y))
+    for dx, dy in [(1, 0), (-1, 0), (0, 1), (0, -1)]:
+        nx = x + dx
+        ny = y + dy
+        if nx >= 0 and ny >= 0 and is_open(nx, ny):
+            q.append((steps + 1, nx, ny))
+
+print(len(seen))

2016/day14/solution.py

@@ -0,0 +1,42 @@
+import hashlib
+import re
+from functools import cache
+
+inp = "ngcjuoqr"
+
+@cache
+def hash_pt1(i):
+    return hashlib.md5((inp + str(i)).encode()).hexdigest()
+
+
+@cache
+def hash_pt2(i):
+    to_hash = inp + str(i)
+    for _ in range(2017):
+        res = hashlib.md5(to_hash.encode()).hexdigest()
+        to_hash = res
+    return res
+
+
+def solve(part2 = False):
+    hash_fct = hash_pt2 if part2 else hash_pt1
+    i = 0
+    n_key = 0
+    while True:
+        three_peat = re.search(r"(.)\1{2,}",hash_fct(i))
+        if three_peat:
+            char = three_peat.group()[0]
+            for j in range(i + 1, i + 1001):
+                if re.search(fr"{re.escape(char)}{{5,}}", hash_fct(j)):
+                    n_key += 1
+                    break
+        if n_key == 64:
+            return i
+        i += 1
+        
+
+# Part 1
+print(solve())
+
+# Part 2
+print(solve(True))