aoc_05.py

"""
Advent of Code - tentative pour J5.

Version initiale utilisée pour répondre au problème, mais très inefficace!
En effet, trop de mémoire est employée, et il faut parcourir toutes les données
avant de connaître les dimensions de la grille.

Daniel Kessler (aka Dalker), le 2021.12.
"""
from itertools import product
import numpy as np

DAY = "05"


class Segment:
    """A segment with all its intermediate integer-located points."""

    def __init__(self, *coords):
        self.x0, self.y0, self.x1, self.y1 = coords
        # print(coords, "is not" if not self.is_diagonal() else "is", "diagonal")

    def __str__(self) -> str:
        return f"segment from ({self.x0}, {self.y0}) to ({self.x1}, {self.y1})."

    def is_diagonal(self) -> bool:
        return self.x0 != self.x1 and self.y0 != self.y1

    def __iter__(self):
        if self.x0 == self.x1:
            ymin, ymax = sorted([self.y0, self.y1])
            return product([self.x0], range(ymin, ymax+1))
        elif self.y0 == self.y1:
            xmin, xmax = sorted([self.x0, self.x1])
            return product(range(xmin, xmax+1), [self.y0])
        else:
            dx = 1 if self.x0 < self.x1 else -1
            dy = 1 if self.y0 < self.y1 else -1
            return zip(range(self.x0, self.x1 + dx, dx),
                       range(self.y0, self.y1 + dy, dy))
        return self


def get_data(fname: str) -> list[str]:
    """Read the day's input and return contents in adequate data structure."""
    try:
        with open(f"{fname}.txt") as datafile:
            data = list(datafile)
    except FileNotFoundError:
        print("Day's data file not found. Using Hint Data instead.")
        return []
    return data


def easy(data: list[str], diagonals=False) -> int:
    """Easy problem of the day."""
    DEBUG = False
    segments = []
    xmax, ymax = 0, 0
    for line in data:
        x0, y0, x1, y1 = (int(n) for endpoint in line.split(" -> ")
                          for n in endpoint.split(","))
        xmax, ymax = max(xmax, x0, x1), max(ymax, y0, y1)
        segments.append(Segment(x0, y0, x1, y1))
    grid = np.zeros((xmax+1, ymax+1))
    for segment in segments:
        if not diagonals and segment.is_diagonal():
            continue
        if DEBUG:
            print("processing", segment)
        for x, y in segment:
            if DEBUG:
                print(x, y, end=", ")
            grid[x, y] += 1
        if DEBUG:
            print()
    if DEBUG:
        print(grid.transpose())
    return sum(value > 1 for row in grid for value in row)


def hard(data: list[str]) -> int:
    """Hard problem of the day."""
    return easy(data, diagonals=True)


if __name__ == "__main__":
    hintdata = get_data(f"hintdata{DAY}")
    realdata = get_data(f"input{DAY}")
    print("check hint 1:", easy(hintdata))
    print("check hint 2:", hard(hintdata))
    print("  solution 1:", easy(realdata))
    print("  solution 2:", hard(realdata))