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AdventOfCode/2020/solutions/day_03.py
2020-12-25 23:50:29 +01:00

60 lines
1.6 KiB
Python

"""AOC Day 3"""
import pathlib
import time
def read_input(input_path: str) -> list:
"""take input file path and return appropriate data structure"""
with open(input_path, 'r') as input_file:
lines = list()
for line in input_file.readlines():
lines.append(line.strip())
return lines
def slope_tree_check(lines: list, dx: int, dy: int) -> int:
"""check how many trees would be encountered with a specific slope"""
x_pos = 0
y_pos = 0
trees_encountered = 0
line_length = len(lines[0])
while y_pos < len(lines):
if lines[y_pos][x_pos] == '#':
trees_encountered += 1
x_pos = (x_pos + dx) % line_length
y_pos += dy
return trees_encountered
def part1(entries: list) -> int:
"""part1 solver take a list of strings and return an int"""
return slope_tree_check(entries, 3, 1)
def part2(entries: list) -> int:
"""part2 solver take a list of tuples and return an int"""
slopes = [
(1, 1),
(3, 1),
(5, 1),
(7, 1),
(1, 2),
]
prod = 1
for slope in slopes:
prod *= slope_tree_check(entries, slope[0], slope[1])
return prod
def main():
"""main function"""
input_path = str(pathlib.Path(__file__).resolve().parent.parent) + "/inputs/" + str(pathlib.Path(__file__).stem)
entries = read_input(input_path)
start_time = time.time()
print("Part 1: %d" % part1(entries))
print("Part 2: %d" % part2(entries))
end_time = time.time()
print("Execution time: %f" % (end_time-start_time))
if __name__ == "__main__":
main()