You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
76 lines
2.0 KiB
76 lines
2.0 KiB
from collections import defaultdict
|
|
import re
|
|
|
|
|
|
EX0 = ["R8,U5,L5,D3", "U7,R6,D4,L4"]
|
|
EX1 = ["R75,D30,R83,U83,L12,D49,R71,U7,L72", "U62,R66,U55,R34,D71,R55,D58,R83"]
|
|
EX2 = ["R98,U47,R26,D63,R33,U87,L62,D20,R33,U53,R51", "U98,R91,D20,R16,D67,R40,U7,R15,U6,R7"]
|
|
|
|
|
|
def main():
|
|
with open("day3.txt", "rt") as input_file:
|
|
lines = list(input_file.readlines())
|
|
solve(lines)
|
|
|
|
def solve(input_lines):
|
|
wires = [(wire_id, line.strip().split(",")) for wire_id, line in enumerate(input_lines)]
|
|
grid = compute_grid(wires)
|
|
|
|
# Part 1
|
|
intersections = [(x, y) for x, l in grid.items() for y, wl in l.items() if len(wl) > 1]
|
|
print("Intersections:", intersections)
|
|
distances = [abs(p[0]) + abs(p[1]) for p in intersections]
|
|
print("Distances:", distances)
|
|
print("Min distance:", min(distances))
|
|
|
|
# Part 2
|
|
min_steps = get_earliest_intersections(grid)
|
|
print(f"Min steps found: {min_steps}.")
|
|
|
|
def compute_grid(wires):
|
|
grid = defaultdict(lambda: defaultdict(list))
|
|
for wire_id, codes in wires:
|
|
fill_grid(wire_id, codes, grid)
|
|
return grid
|
|
|
|
CODE_RE = re.compile(r"(\w)(\d+)")
|
|
|
|
MOVES = {
|
|
"R": (0, +1),
|
|
"L": (0, -1),
|
|
"U": (+1, 0),
|
|
"D": (-1, 0),
|
|
}
|
|
|
|
def fill_grid(wire_id, codes, grid):
|
|
x = 0
|
|
y = 0
|
|
steps = 0
|
|
for code in codes:
|
|
match = CODE_RE.match(code)
|
|
op, arg = match.groups()
|
|
for _ in range(int(arg)):
|
|
move = MOVES[op]
|
|
x, y = x + move[0], y + move[1]
|
|
steps += 1
|
|
inc_point((x, y), grid, wire_id, steps)
|
|
|
|
def inc_point(point, grid, wire_id, steps):
|
|
x, y = point
|
|
if wire_id not in [wid for wid, s in grid[x][y]]:
|
|
grid[x][y].append((wire_id, steps))
|
|
|
|
def get_earliest_intersections(grid):
|
|
min_steps = 2**64
|
|
for line in grid.values():
|
|
for wire_ids in line.values():
|
|
if len(wire_ids) > 1:
|
|
steps = sum(s for _, s in wire_ids)
|
|
if steps < min_steps:
|
|
min_steps = steps
|
|
return min_steps
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|