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# Advent of Code day 21: it's a marathon, not a sprint

22 Dec, 2019

….Aaaand here we are, in the last stretch of the #AdventOfCode 2019 puzzle-a-ganza! Like every year, the evil genius that is Eric Wastl has ramped up the puzzles gradually, and we’re now at those puzzles that you look at and go: "oof, another one? I just finished the previous day!"

And not just that, Advent of Code makes me act in a way befitting the Christmas theme. Trying to solve these puzzles has made me raise my eyes to heaven and pray for inspiration more than once – even though I’m an atheist :-).

It shows in my visualization code. Whereas my first visualizers were nifty things with graphics and curses, now all I just want to plunk some quick print statements in there to see what’s going on. So was born the PrintVisualiser, the little brother of Visualizer and CursesVisualizer.

It turned out to have a nice side benefit. I’m trying to stay away from "cheating" with numpy, and it turns out that for a sparse matrix, or even a not-so-sparse matrix, just using a dictionary indexed by x,y tuple works perfectly fine!

class PrintVisualizer(object):
"""Simplest visualizer, simply generates a bunch of print() statements."""
def __init__(self, area: (Point, Point) = None, default_char=EMPTY):
self.points = dict()
self.default_char = default_char
self.area = area
def plot(self, xy, c):
self.points[xy] = c
if self.area:
min_xy, max_xy = self.area
else:
for y in range(min_xy.y, max_xy.y + 1):
line = list()
for x in range(min_xy.x, max_xy.x + 1):
if (x, y) in self.points:
line.append(self.points[(x, y)])
else:
line.append(self.default_char)
print(''.join(line))


So, off to my last few days: let’s see if I can finish more than the 21 days I succeeded in last year!

Questions?