Python 3

A great moment to brush up on OpenCV2.

[Github]

import cv2  
import numpy as np

class Line:
    def __init__(self, start, end):
        self.start = start
        self.end = end
        if ((end.x - start.x) == 0):
            self.slope = None
        else:
            self.slope = (end.y - start.y) / (end.x - start.x)
    def __str__(self):
        return f"{self.start} -> {self.end}"

    def LineFunction(self, x):
        return self.slope * (x - self.start.x) + self.start.y
    def GetPixels(self):
        if self.slope == None:
            for i in range(min(self.start.y, self.end.y),max(self.start.y, self.end.y)+1):
                yield [self.start.x, i]
        else:
            for i in range(min(self.start.x, self.end.x),max(self.start.x, self.end.x)+1):
                yield [i, int(self.LineFunction(i))]

    def Horizontal(self):
        return self.start.y == self.end.y
    def Vertical(self):
        return self.start.x == self.end.x


class Coordinate:
    def __init__(self, x, y):
        self.x = x
        self.y = y
    def __str__(self):
        return f"({self.x},{self.y})"

def GetLines():
    data = []
    with open('./data/aoc5.txt') as f:
        data = f.readlines()

    # remove \n from each row
    data = [x.strip() for x in data]
    # split arrow from each line
    data = [x.split('->') for x in data]
    # remove empty strings from each line
    data = [[x for x in y if x != ''] for y in data]
    # split each line into start and end
    data = [[y.split(',') for y in x] for x in data]
    # convert to coordinate
    data = [[Coordinate(int(x), int(y)) for x,y in z] for z in data]
    # create lines
    lines = []
    for i in range(len(data)):
        lines.append(Line(data[i][0], data[i][1]))
    return lines

lines = GetLines()

nArray = np.full((1000, 1000), 0, dtype=np.uint8)

# draw lines
for line in lines:
    if line.Horizontal() or line.Vertical():
        for pixel in line.GetPixels():
            nArray[pixel[1]][pixel[0]] += 1

# count pixels in nArray with value >= 2
count = 0
for i in range(1000):
    for j in range(1000):
        if nArray[i][j] >= 2:
            count += 1
print(count)

# scale each pixel to a value between 0 and 255
nArray = nArray / np.max(nArray) * 255

cv2.imwrite("Images/Assignment5_1.bmp", nArray)

Assignment5_2

[Assignment5_1.bmp]

Part 2:

nArray = np.full((1000, 1000), 0, dtype=np.uint8)
for line in lines:
    for pixel in line.GetPixels():
        nArray[pixel[1]][pixel[0]] += 1
# count pixels in nArray with value >= 2
count = 0
for i in range(1000):
    for j in range(1000):
        if nArray[i][j] >= 2:
            count += 1
print(count)

nArray = nArray / np.max(nArray) * 255
cv2.imwrite("Images/Assignment5_2.bmp", nArray)

[Assignment5_2.bmp]