AOC 2018 - Day 6 - Python

aoc2018_day6.py

# Input and shared code between parts

coords = [tuple(int(c) for c in line.strip().split(',')) for line in open('day6.txt')]

xMax = max(coords, key=lambda c: c[0])[0]
yMax = max(coords, key=lambda c: c[1])[1]

def manhattanDistance(p, q):
    return abs(p[0] - q[0]) + abs(p[1] - q[1]);
    
# Part 1

grid = {}
closestCount = {}
infinites = set()

for y in range(-1, yMax + 1):
    for x in range(-1, xMax + 1):
        minDistance = -1
        closest = None
        for coord in coords:
            distance = manhattanDistance(coord, (x, y))
            if minDistance == -1 or minDistance > distance:
                minDistance = distance
                closest = coord
            elif minDistance == distance:
                closest = None
        grid[(x, y)] = closest
        if closest not in closestCount:
            closestCount[closest] = 0
        closestCount[closest] += 1

for y in [-1, yMax]:
    for x in range(-1, xMax + 1):
        if (x, y) in grid:
            closest = grid[(x, y)]
            infinites.add(closest)
for x in [-1, xMax]:
    for y in range(-1, yMax + 1):
        if (x, y) in grid:
            closest = grid[(x, y)]
            infinites.add(closest)

closestCount = {coord: closestCount[coord] for coord in closestCount if coord not in infinites}
print(max(closestCount.items(), key=lambda c: c[1])[1])

# Part 2

maxDistance = 10000
patchCount = 0
for y in range(-1, yMax + 1):
    for x in range(-1, xMax + 1):
        totalDistance = 0
        for coord in coords:
            totalDistance += manhattanDistance(coord, (x, y))
        if totalDistance < maxDistance:
            patchCount += 1
print(patchCount)