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advent-of-code/2020/days/03/day3.py

49 lines
1.1 KiB
Python
Executable file

#! /usr/bin/env python3
import pathlib
import sys
def parse(puzzle_input: str):
"""Parse input"""
# returns a 2 dimentional array where true means there is a tree there.
return [[i == "#" for i in j] for j in puzzle_input.splitlines()]
def part1(data):
"""Solve part 1"""
return solveForSlope(data, 3, 1)
def solveForSlope(data, right: int, down: int):
return sum(
1 for index, row in enumerate(data[::down]) if row[(right * index) % len(row)]
)
def part2(data):
"""Solve part 2"""
return (
solveForSlope(data, 1, 1)
* solveForSlope(data, 3, 1)
* solveForSlope(data, 5, 1)
* solveForSlope(data, 7, 1)
* solveForSlope(data, 1, 2)
)
def solve(puzzle_input):
"""Solve the puzzle for the given input"""
data = parse(puzzle_input)
solution1 = part1(data)
solution2 = part2(data)
return solution1, solution2
if __name__ == "__main__":
for path in sys.argv[1:]:
print(f"{path}:")
puzzle_input = pathlib.Path(path).read_text().strip()
solutions = solve(puzzle_input)
print("\n".join(str(solution) for solution in solutions))