17.py

import fileinput
import re

class Model:
    def __init__(self, lines):
        self.clay = set()
        self.still = set()
        self.flowing = set()
        for line in lines:
            a, b0, b1 = map(int, re.findall(r'\d+', line))
            for b in range(b0, b1 + 1):
                self.clay.add((a, b) if line[0] == 'x' else (b, a))
        self.x0 = min(x for x, y in self.clay)
        self.x1 = max(x for x, y in self.clay)
        self.y0 = min(y for x, y in self.clay)
        self.y1 = max(y for x, y in self.clay)
        self.queue = []

    def run(self, x, y):
        self.queue.append((self.fall, x, y))
        while self.queue:
            func, *args = self.queue.pop()
            func(*args)

    def count_all(self):
        return sum(1 for x, y in self.still | self.flowing
            if y >= self.y0 and y <= self.y1)

    def count_still(self):
        return sum(1 for x, y in self.still
            if y >= self.y0 and y <= self.y1)

    def stop(self, x, y):
        return (x, y) in self.clay

    def pile(self, x, y):
        return (x, y) in self.clay or (x, y) in self.still

    def fall(self, x, y):
        while y <= self.y1 and not self.pile(x, y + 1):
            self.flowing.add((x, y))
            y += 1
        if y <= self.y1:
            self.flowing.add((x, y))
            self.queue.append((self.scan, x, y))

    def scan(self, x, y):
        x0 = x
        while self.pile(x0, y + 1) and not self.stop(x0 - 1, y):
            x0 -= 1
        x1 = x
        while self.pile(x1, y + 1) and not self.stop(x1 + 1, y):
            x1 += 1
        stop0 = self.stop(x0 - 1, y)
        stop1 = self.stop(x1 + 1, y)
        if stop0 and stop1:
            for i in range(x0, x1 + 1):
                self.still.add((i, y))
            self.queue.append((self.scan, x, y - 1))
        else:
            for i in range(x0, x1 + 1):
                self.flowing.add((i, y))
            if not stop0:
                self.queue.append((self.fall, x0, y))
            if not stop1:
                self.queue.append((self.fall, x1, y))

    def __str__(self):
        x0, y0, x1, y1 = self.x0, self.y0, self.x1, self.y1
        rows = []
        for y in range(y0, y1 + 1):
            row = []
            for x in range(x0, x1 + 1):
                c = '.'
                if (x, y) in self.clay:
                    c = '#'
                if (x, y) in self.flowing:
                    c = '|'
                if (x, y) in self.still:
                    c = '~'
                row.append(c)
            rows.append(''.join(row))
        return '\n'.join(rows)

model = Model(fileinput.input())
model.run(500, 0)
print(model)
print(model.count_all())
print(model.count_still())