Day 14

Author: Iain530

.gitignore

@@ -1,4 +1,5 @@
 __pycache__
 .sessioncookie
 
-venv
+venv
+.DS_Store

2022/14/input.txt

@@ -0,0 +1,146 @@
+import numpy as np
+import matplotlib.pyplot as plt
+from matplotlib import animation
+from utils import read_input, run, sliding_window
+
+
+FNAME = "14/input.txt"
+WALL = 1
+SAND = 2
+
+def parse_chunk(line):
+    return [tuple(map(int, coord.split(','))) for coord in line.split(' -> ')]
+
+
+##########
+# PART 1 #
+##########
+
+
+def line_points(start, end):
+    x1, y1 = start
+    x2, y2 = end
+    if x1 == x2:
+        return [(x1, y) for y in range(min(y1, y2), max(y1, y2) + 1)]
+    elif y1 == y2:
+        return [(x, y1) for x in range(min(x1, x2), max(x1, x2) + 1)]
+
+
+def build_grid(lines):
+    max_y = max(y for l in lines for _, y in l) + 3
+    grid = np.zeros((1001, max_y))
+
+    for line in lines:
+        for start, end in sliding_window(line, 2):
+            for point in line_points(start, end):
+                grid[point] = WALL
+
+    return grid
+
+
+def try_move(grid, sand):
+    x, y = sand
+    next_y = y + 1
+    if x == 0:
+        raise Exception(f'{sand}')
+    if not grid[(x, next_y)]:
+        return (x, next_y)
+    if not grid[(x-1, next_y)]:
+        return (x-1, next_y)
+    if not grid[(x+1, next_y)]:
+        return (x+1, next_y)
+    
+    return sand
+
+
+def simulate_sand(grid):
+    current = (500, 0)
+    if grid[current]:
+        return False  # Full
+
+    while True:
+        next_position = try_move(grid, current)
+        if next_position == current:
+            grid[current] = SAND
+            return True  # Landed
+        
+        if next_position[1] == grid.shape[1] - 1:
+            return False  # Abyss
+
+        current = next_position
+
+
+def part_one(input_file):
+    grid = build_grid(read_input(input_file, parse_chunk=parse_chunk))
+
+    landed = 0
+    while simulate_sand(grid):
+        landed += 1
+
+    # def next_grid():
+    #     simulate_sand(grid)
+    #     return grid
+    
+    # show(grid, frames=862, next_grid=next_grid)
+    
+    return landed
+    
+
+
+
+##########
+# PART 2 #
+##########
+
+
+def part_two(input_file):
+    grid = build_grid(read_input(input_file, parse_chunk=parse_chunk))
+    grid[:, grid.shape[1] - 1] = WALL
+
+    landed = 0
+    while simulate_sand(grid):
+        landed += 1
+    
+    # def next_grid():
+    #     for i in range(30):
+    #         simulate_sand(grid)
+    #     return grid
+
+    # show(grid, frames=925, next_grid=next_grid)
+
+    return landed
+
+
+def show(grid, frames, next_grid):
+    def format(grid):
+        return grid.T[:,350:650]
+
+    fig = plt.figure()
+    im = plt.imshow(format(grid), animated=True, cmap='viridis', vmin=0, vmax=2)
+    plt.tight_layout()
+    plt.grid(False)
+    plt.axis('off')
+
+    def init():
+        im.set_data(format(grid))
+        return im,
+
+    def animate(i):
+        im.set_array(format(next_grid()))
+        return im,
+
+    anim = animation.FuncAnimation(
+        fig,
+        animate,
+        init_func=init,
+        frames=frames,
+        interval=1,
+        blit=True,
+    )
+
+    anim.save(f"sand_{frames}.gif")
+    plt.show()
+
+
+if __name__ == '__main__':
+    run(part_one, part_two, FNAME)