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My Advent of Code solutions in Python. kevinyap.ca/2019/12/going-fast-in-advent-of-code
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LETTERS = [x for x in 'abcdefghijklmnopqrstuvwxyz']VOWELS = {'a', 'e', 'i', 'o', 'u'}CONSONANTS = set(x for x in LETTERS if x not in VOWELS)
def parse_line(regex, line): ret = [] for match in re.match(regex, line).groups(): try: ret.append(int(match)) except ValueError: ret.append(match)
return ret
def parse_nums(line, negatives=True): num_re = r'-?\d+' if negatives else r'\d+' return [int(n) for n in re.findall(num_re, line)]
def new_table(val, width, height): return [[val for _ in range(width)] for _ in range(height)]
def transposed(matrix): """Returns the transpose of the given matrix.""" return [list(r) for r in zip(*matrix)]
def rotated(matrix): """Returns the given matrix rotated 90 degrees clockwise.""" return [list(r) for r in zip(*matrix[::-1])]
def mul(lst): """Like sum(), but for multiplication.""" return reduce(operator.mul, lst, 1) # NOQA
def chunks(l, n): """Yield successive n-sized chunks from l.""" for i in range(0, len(l), n): yield l[i:i + n]
def all_unique(lst): return len(lst) == len(set(lst))
def factors(n): """Returns the factors of n.""" return sorted( x for tup in ( [i, n // i] for i in range(1, int(n ** 0.5) + 1) if n % i == 0) for x in tup)
def gcd(a,b): """Compute the greatest common divisor of a and b""" while b > 0: a, b = b, a % b return a
def lcm(a, b): """Compute the lowest common multiple of a and b""" return a * b / gcd(a, b)
def egcd(a, b): x0, x1, y0, y1 = 1, 0, 0, 1 while b: q, a, b = a // b, b, a % b x0, x1 = x1, x0 - q * x1 y0, y1 = y1, y0 - q * y1 return a, x0, y0
def modinv(a, n): g, x, _ = egcd(a, n) if g == 1: return x % n else: raise ValueError("%d is not invertible mod %d" % (a, n))
def crt(rems, mods): ''' Solve a system of modular equivalences via the Chinese Remainder Theorem. Does not require pairwise coprime moduli. '''
# copy inputs orems, omods = rems, mods rems = list(rems) mods = list(mods)
newrems = [] newmods = []
for i in range(len(mods)): for j in range(i+1, len(mods)): g = gcd(mods[i], mods[j]) if g == 1: continue if rems[i] % g != rems[j] % g: raise ValueError("inconsistent remainders at positions %d and %d (mod %d)" % (i, j, g)) mods[j] //= g
while 1: # transfer any remaining gcds to mods[j] g = gcd(mods[i], mods[j]) if g == 1: break mods[i] //= g mods[j] *= g
if mods[i] == 1: continue
newrems.append(rems[i] % mods[i]) newmods.append(mods[i])
rems, mods = newrems, newmods
# standard CRT s = 0 n = 1 for k in mods: n *= k
for i in range(len(mods)): ni = n // mods[i] s += rems[i] * modinv(ni, mods[i]) * ni return s % n, n
def min_max_xy(points): if len(points) == 0: return None, None, None, None if type(points[0]) == tuple: min_x = min(p[0] for p in points) max_x = max(p[0] for p in points) min_y = min(p[1] for p in points) max_y = max(p[1] for p in points) else: min_x = min(p.x for p in points) max_x = max(p.x for p in points) min_y = min(p.y for p in points) max_y = max(p.y for p in points)
return min_x, max_x, min_y, max_y
def print_grid(grid, f=None, quiet=False): if f is None: f = lambda x: x # NOQA
counts = Counter() serialized = []
if type(grid) is dict: positions = grid.keys() min_x, max_x, min_y, max_y = min_max_xy(positions) if type(positions[0]) is tuple: for y in range(min_y, max_y + 1): row = ''.join(f(grid.get((x, y), ' ')) for x in range(min_x, max_x + 1)) if not quiet: print row serialized.append(row) for c in row: counts[c] += 1
else: # (x, y) => point for y in range(min_y, max_y + 1): row = ''.join(f(grid.get(Point(x, y), ' ')) for x in range(min_x, max_x + 1)) if not quiet: print row serialized.append(row) for c in row: counts[c] += 1 else: for y in range(len(grid)): row = ''.join(f(grid[y][x]) for x in range(len(grid[0]))) if not quiet: print row serialized.append(row) for c in row: counts[c] += 1
# if not quiet: # print "height={} ({} -> {})".format(max_y - min_y + 1, min_y, max_y) # print "width={} ({} -> {})".format(max_x - min_x + 1, min_x, max_x) # print "Statistics:" # for item, num in counts.most_common(): # print "{}: {}".format(item, num)
return serialized
def resolve_mapping(candidates): resolved = {}
# Ensure the mapping is key -> set(values). candidates_map = {} for k, v in candidates.items(): candidates_map[k] = set(v)
while len(resolved) < len(candidates_map): for candidate in candidates_map: if len(candidates_map[candidate]) == 1 and candidate not in resolved: r = candidates_map[candidate].pop() for c in candidates_map: candidates_map[c].discard(r)
resolved[candidate] = r break
return resolved
def memoize(f): """Simple dictionary-based memoization decorator""" cache = {}
def _mem_fn(*args): hargs = (','.join(str(x) for x in args)) if hargs not in cache: cache[hargs] = f(*args) return cache[hargs]
_mem_fn.cache = cache return _mem_fn
def _eratosthenes(n): """http://stackoverflow.com/a/3941967/239076""" # Initialize list of primes _primes = [True] * n
# Set 0 and 1 to non-prime _primes[0] = _primes[1] = False
for i, is_prime in enumerate(_primes): if is_prime: yield i
# Mark factors as non-prime for j in xrange(i * i, n, i): # NOQA _primes[j] = False
def primes(n): """Return a list of primes from [2, n)""" return list(_eratosthenes(n))
def md5(msg): m = hashlib.md5() m.update(msg) return m.hexdigest()
def sha256(msg): s = hashlib.sha256() s.update(msg) return s.hexdigest()
def knot_hash(msg): lengths = [ord(x) for x in msg] + [17, 31, 73, 47, 23] sparse = range(0, 256) pos = 0 skip = 0
for _ in range(64): for l in lengths: for i in range(l // 2): x = (pos + i) % len(sparse) y = (pos + l - i - 1) % len(sparse) sparse[x], sparse[y] = sparse[y], sparse[x]
pos = pos + l + skip % len(sparse) skip += 1
hash_val = 0
for i in range(16): res = 0 for j in range(0, 16): res ^= sparse[(i * 16) + j]
hash_val += res << ((16 - i - 1) * 8)
return '%032x' % hash_val
HEX_DIRS = { 'N': (1, -1, 0), 'NE': (1, 0, -1), 'SE': (0, 1, -1), 'S': (-1, 1, 0), 'SW': (-1, 0, 1), 'NW': (0, -1, 1),}
def hex_distance(x, y, z): """Returns a given hex point's distance from the origin.""" return (abs(x) + abs(y) + abs(z)) // 2
@total_orderingclass Point: """Simple 2-dimensional point.""" def __init__(self, x, y): self.x = x self.y = y
def __add__(self, other): return Point(self.x + other.x, self.y + other.y)
def __sub__(self, other): return Point(self.x - other.x, self.y - other.y)
def __mul__(self, n): return Point(self.x * n, self.y * n)
def __div__(self, n): return Point(self.x / n, self.y / n)
def __neg__(self): return Point(-self.x, -self.y)
def __eq__(self, other): return self.x == other.x and self.y == other.y
def __ne__(self, other): return not self == other
def __lt__(self, other): return self.length < other.length
def __str__(self): return "({}, {})".format(self.x, self.y)
def __repr__(self): return "Point({}, {})".format(self.x, self.y)
def __hash__(self): return hash(tuple((self.x, self.y)))
def dist(self, other): return math.sqrt((self.x - other.x) ** 2 + (self.y - other.y) ** 2)
def dist_manhattan(self, other): return abs(self.x - other.x) + abs(self.y - other.y)
def angle(self, to=None): if to is None: return math.atan2(self.y, self.x) return math.atan2(self.y - to.y, self.x - to.x)
def rotate(self, turns): """Returns the rotation of the Point around (0, 0) `turn` times clockwise.""" turns = turns % 4
if turns == 1: return Point(self.y, -self.x) elif turns == 2: return Point(-self.x, -self.y) elif turns == 3: return Point(-self.y, self.x) else: return self
@property def manhattan(self): return abs(self.x) + abs(self.y)
@property def length(self): return math.sqrt(self.x ** 2 + self.y ** 2)
def neighbours_4(self): return [self + p for p in DIRS_4]
def neighbors_4(self): return self.neighbours_4()
def neighbours(self): return self.neighbours_4()
def neighbors(self): return self.neighbours()
def neighbours_8(self): return [self + p for p in DIRS_8]
def neighbors_8(self): return self.neighbours_8()
DIRS_4 = DIRS = [ Point(0, 1), # north Point(1, 0), # east Point(0, -1), # south Point(-1, 0), # west]
DIRS_8 = [ Point(0, 1), # N Point(1, 1), # NE Point(1, 0), # E Point(1, -1), # SE Point(0, -1), # S Point(-1, -1), # SW Point(-1, 0), # W Point(-1, 1), # NW]