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First solution in Clear category for Fortress Cannons by mortonfox
from itertools import product, chain
DIRECTIONS = ['N', 'NE', 'SE', 'S', 'SW', 'NW']
# Return the coordinates resulting from a move in the specified direction.
def move(coord, direction):
col, row = coord
if direction == 0: # N
return (col, row - 1)
if direction == 1: # NE
return (col + 1, (row - 1 if col % 2 else row))
if direction == 2: # SE
return (col + 1, (row if col % 2 else row + 1))
if direction == 3: # S
return (col, row + 1)
if direction == 4: # SW
return (col - 1, (row if col % 2 else row + 1))
if direction == 5: # NW
return (col - 1, (row - 1 if col % 2 else row))
# Return a list of all cells covered by the cannon if fired in the specified direction.
def cannon_range(coord, direction, cannon):
arc, minrange, maxrange = cannon
result = []
ldir = (direction - 2) % 6
rdir = (direction + 2) % 6
for dist in range(minrange, maxrange + 1):
point = coord
for i in range(dist):
point = move(point, direction)
result.append(point)
spread = 0
if arc == 60:
spread = dist // 2
elif arc == 120:
spread = dist
point1 = point
point2 = point
for i in range(spread):
point1 = move(point1, ldir)
result.append(point1)
point2 = move(point2, rdir)
result.append(point2)
return result
# Convert string coord to numeric coord.
def conv_to_coord(coordstr):
return (ord(coordstr[0]) - ord('A') + 1, int(coordstr[1]))
def fortress_cannons(fort, cannons, enemies):
fort_coord = conv_to_coord(fort)
enemy_set = set(conv_to_coord(e) for e in enemies)
# Point each cannon in each direction and record which enemies get hit.
cannon_hits = [[enemy_set.intersection(cannon_range(fort_coord, direction, cannon)) for direction in range(6)] for cannon in cannons]
# Find a set of cannon directions that covers all enemies.
for dirset in product(range(6), repeat=len(cannons)):
if enemy_set == set(chain.from_iterable(cannon_hit[direction] for direction, cannon_hit in zip(dirset, cannon_hits))):
return [DIRECTIONS[direction] for direction in dirset]
return None
if __name__ == '__main__':
assert fortress_cannons('F5', [(0, 1, 4)], {'F2'}) == ['N'], '0 degree'
assert fortress_cannons('F5', [(60, 1, 6)], {'K4'}) == ['NE'], '60 degree'
assert fortress_cannons('F5', [(120, 1, 4)],{'B3', 'E8'}) == ['SW'], '120 degree'
assert fortress_cannons('F5', [(0, 2, 6), (120, 1, 3), (60, 1, 4)], {'L2', 'D3', 'C6', 'E9'}) == ['NE', 'NW', 'S'], '3 cannons'
assert fortress_cannons('F5', [(0, 1, 6), (120, 2, 3)], {'A3', 'E6', 'G7'}) is None, 'None'
print("Coding complete? Click 'Check' to earn cool rewards!")
Jan. 9, 2019
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