🦀

toolkit.py

@@ -1,7 +1,9 @@
 import collections
 
 
-def render(grid, brush):
+def render(grid, brush=None):
+    if brush is None:
+        brush = {v: v for v in grid.values()}
     if isinstance(brush, str):
         brush = {i: c for i, c in enumerate(brush)}
     xmin, *_, xmax = sorted(int(p.real) for p in grid)
@@ -15,25 +17,29 @@ def render(grid, brush):
     return rendered
 
 
-def bsearch(fn, goal, lo, hi):
-    while hi - lo > 1:
-        mid = lo + (hi - lo) // 2
-        if goal < fn(mid):
-            lo, hi = lo, mid
-        else:
-            lo, hi = mid, hi
-
-    # check
-    a, b = fn(lo), fn(hi)
-    assert a <= goal, 'lower bound too high'
-    assert goal <= b, 'higher bound too low'
-
-    return lo
-
-
 def read_image(text):
     grid = collections.defaultdict(str)
     for y, line in enumerate(text.splitlines()):
         for x, cell in enumerate(line):
             grid[complex(x, y)] = cell
     return grid
+
+
+def shortest_path(start, end, move):
+    seen = {}
+    edge = {start: None}
+    while end not in seen:
+        seen.update(edge)
+        edge = {
+            adj: pos
+            for pos in edge
+            for adj in move(pos)
+            if adj not in seen
+        }
+        if not edge:
+            raise RuntimeError('Path not found', seen)
+    path = []
+    while end:
+        path.append(end)
+        end = seen[end]
+    return path[::-1]

y2019/p14.py

@@ -3,8 +3,6 @@ import math
 import re
 import sys
 
-from toolkit import bsearch
-
 
 text = sys.stdin.read()
 cookbook = {}
@@ -29,5 +27,21 @@ def fuel_to_ore(state):
     return state
 
 
+def bsearch(fn, goal, lo, hi):
+    while hi - lo > 1:
+        mid = lo + (hi - lo) // 2
+        if goal < fn(mid):
+            lo, hi = lo, mid
+        else:
+            lo, hi = mid, hi
+
+    # check
+    a, b = fn(lo), fn(hi)
+    assert a <= goal, 'lower bound too high'
+    assert goal <= b, 'higher bound too low'
+
+    return lo
+
+
 print(fuel_to_ore({'FUEL': 1})['ORE'])
 print(bsearch(lambda n: fuel_to_ore({'FUEL': n})['ORE'], 1E12, 1, 10_000_000))

y2019/p18.py

@@ -0,0 +1,119 @@
+import collections
+import itertools
+import sys
+
+from toolkit import read_image, render
+
+
+def read_in(text):
+    grid = read_image(text)
+    elements = {v: k for k, v in grid.items()}
+    keys = frozenset(k for k in elements if 'a' <= k <= 'z')
+    return dict(grid), elements, keys
+
+
+def move(pos):
+    for ori in [1, -1, 1j, -1j]:
+        if grid[pos + ori] != '#':
+            yield pos + ori
+
+
+def shortest_path(start, end, move):
+    seen = {}
+    edge = {start: None}
+    while end not in seen:
+        edge = {
+            adj: pos
+            for pos in edge
+            for adj in move(pos)
+            if adj not in seen
+        }
+        seen.update(edge)
+        if not edge:
+            raise RuntimeError('No path found')
+    path = []
+    while end != start:
+        path.append(end)
+        end = seen[end]
+    return path
+
+
+def trim(states):
+    groups = collections.defaultdict(list)
+    for state in states:
+        tips = frozenset(seq[-1] for seq in state)
+        bulk = frozenset(' '.join(state))
+        groups[bulk, tips].append(state)
+    return [min(groups[k], key=calc_total) for k in groups]
+
+
+def precalc_moves(entrances):
+    requirements = collections.defaultdict(dict)
+    lengths = collections.defaultdict(dict)
+    for a, b in itertools.permutations(keys.union(entrances), 2):
+        try:
+            path = shortest_path(elements[a], elements[b], move)
+        except RuntimeError:
+            continue
+        lengths[a][b] = len(path)
+        requirements[a][b] = {
+            e.lower()
+            for e, v in elements.items()
+            if e.isupper()
+            and v in path
+        }
+    return requirements, lengths
+
+
+def calc_total(state):
+    return sum(sum(
+        lengths[a][b]
+        for a, b in zip(s, s[1:])
+        if {a, b} < set(lengths)
+    ) for s in state)
+
+
+def mod_grid(text):
+    grid, elements, keys = read_in(text)
+    pos = elements['@']
+    grid[pos] = '#'
+    for char, ori in zip('*&^@', [1, -1, 1j, -1j]):
+        grid[pos + ori] = '#'
+        grid[pos + ori + ori * 1j] = char
+    return render(grid, {k: k for k in grid.values()})
+
+
+def solve(text):
+    global grid, elements, keys, lengths
+    grid, elements, keys = read_in(text)
+    stacks = {k for k in elements if not k.isalnum()} - {'#', '.'}
+    requirements, lengths = precalc_moves(stacks)
+    states = [stacks]
+    for _ in range(len(keys)):
+        states = trim(
+            state - {seq} | {seq + b}
+            for state in states
+            for seq in state
+            for b, reqs in requirements[seq[-1]].items()
+            if b not in seq and reqs.issubset(''.join(state))
+        )
+    final = min(states, key=calc_total)
+    print(' '.join(sorted(final)))
+    print(calc_total(final))
+
+
+text = sys.stdin.read()
+text = '''
+#############
+#g#f.D#..h#l#
+#F###e#E###.#
+#dCba...BcIJ#
+#####.@.#####
+#nK.L...G...#
+#M###N#H###.#
+#o#m..#i#jk.#
+#############
+'''
+solve(text)
+text = mod_grid(text)
+solve(text)

y2019/p19.py

@@ -0,0 +1,19 @@
+import sys
+
+from intcode import compute
+
+
+def check(x, y):
+    return next(compute(text, iter([x, y])))
+
+
+text = sys.stdin.read()
+tiles = {(x, y) for x in range(50) for y in range(50) if check(x, y)}
+print(len(tiles))
+
+x, y = 0, 0
+while not check(x + 99, y):
+    y += 1
+    while not check(x, y + 99):
+        x += 1
+print(x * 10_000 + y)

y2019/p20.py

@@ -0,0 +1,66 @@
+import itertools
+import sys
+
+from toolkit import read_image, shortest_path
+
+
+def move(pos):
+    for ori in [1, -1, 1j, -1j]:
+        adj = pos + ori
+        if adj in grid:
+            yield adj
+        if adj in duals:
+            yield from move(duals[adj])
+
+
+def move_with_depth(state):
+    pos, level = state
+    for ori in [1, -1, 1j, -1j]:
+        adj = pos + ori
+        if adj in grid:
+            yield adj, level
+        if adj in duals:
+            name = grid[adj]
+            if adj in inner:
+                yield from move_with_depth((duals[adj], level + 1))
+            elif (level > 0) and (name not in {'AA', 'ZZ'}):
+                yield from move_with_depth((duals[adj], level - 1))
+
+
+# base
+text = sys.stdin.read()
+grid = {pos: val for pos, val in read_image(text).items() if val not in ' #'}
+for pos, val in grid.copy().items():
+    if val.isupper():
+        for im in [1, 1j]:
+            A, B, C = [pos - im, pos, pos + im]
+            seq = ''.join(grid.get(p, ' ') for p in [A, B, C])
+            if seq.endswith('.'):
+                grid[B] = grid.pop(A) + grid.pop(B)
+            if seq.startswith('.'):
+                grid[B] = grid.pop(B) + grid.pop(C)
+elements = {v: k for k, v in grid.items()}
+
+# matrix
+duals = {}
+portals = {pos for pos, cell in grid.items() if cell.isupper()}
+for pA, pB in itertools.combinations(portals, 2):
+    if grid[pA] == grid[pB]:
+        duals[pA] = pB
+        duals[pB] = pA
+
+# part1
+start, end = elements['AA'], elements['ZZ']
+path = shortest_path(start, end, move)
+print(len(path) - 3)
+
+# categorize portals
+_, *xmid, _ = sorted({p.real for p in portals})
+_, *ymid, _ = sorted({p.imag for p in portals})
+inner = {pos for pos in portals if pos.real in xmid and pos.imag in ymid}
+outer = set(portals) - inner
+
+# part2
+start, end = (elements['AA'], 0), (elements['ZZ'], 0)
+path = shortest_path(start, end, move_with_depth)
+print(len(path) - 3)