Add 2023/22 py

erikw · web-flow · commit 1dd1c0f98e8f · 2025-05-18T06:12:27.000Z
diff --git a/2023/17/part1_naive.py b/2023/17/part1_naive.py
@@ -95,7 +95,7 @@ def dir_count(pos, prev, dir):
 # heat_map[B].
 # https://en.wikipedia.org/wiki/Constrained_Shortest_Path_First
 def constrained_dijkstra(heat_map, rows, cols, pos_start, pos_end):
-    que = PriorityQueue() # TODO make a heapq version for comparison
+    que = PriorityQueue()
     dist = defaultdict(lambda: float('inf')) # pos -> dist
     prev = defaultdict(lambda: (None, None)) # pos -> (prev_pos, direction_prev_pos_to_pos)
     visited = set()
diff --git a/2023/22/README.md b/2023/22/README.md
@@ -0,0 +1,12 @@
+# Advent of Code - 2023 Day 22
+Here are my solutions to this puzzle.
+
+* Problem instructions: [adventofcode.com/2023/day/22](https://adventofcode.com/2023/day/22)
+* Input: [adventofcode.com/2023/day/22/input](https://adventofcode.com/2023/day/22/input)
+
+Fetch input by exporting `$AOC_SESSION` in your shell and then:
+```bash
+curl -OJLsb session=$AOC_SESSION adventofcode.com/2023/day/22/input
+```
+
+or run `fetch_input.sh` in this directory.
diff --git a/2023/22/fetch_input.sh b/2023/22/fetch_input.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/env sh
+# Make sure $AOC_SESSION is exported before running this script.
+
+curl --remote-name --remote-header-name --silent --fail -A 'https://erikw.me/contact' --cookie "session=$AOC_SESSION" "https://adventofcode.com/2023/day/22/input"
+test "$?" -eq 0 && echo "Fetched input" && exit 0 || echo "Failed to fetch input" && exit 1
diff --git a/2023/22/input1.0 b/2023/22/input1.0
@@ -0,0 +1,7 @@
+1,0,1~1,2,1
+0,0,2~2,0,2
+0,2,3~2,2,3
+0,0,4~0,2,4
+2,0,5~2,2,5
+0,1,6~2,1,6
+1,1,8~1,1,9
diff --git a/2023/22/instructions.url b/2023/22/instructions.url
@@ -0,0 +1,2 @@
+[InternetShortcut]
+URL = https://adventofcode.com/2023/day/22
diff --git a/2023/22/output1.0 b/2023/22/output1.0
@@ -0,0 +1 @@
+5
diff --git a/2023/22/output2.0 b/2023/22/output2.0
@@ -0,0 +1 @@
+7
diff --git a/2023/22/part1.py b/2023/22/part1.py
@@ -0,0 +1,152 @@
+#!/usr/bin/env python3
+import fileinput
+from pprint import pprint
+from collections import defaultdict
+
+SYM_EMPTY = "."
+SYM_HIDDEN = "?"
+
+def read_bricks():
+    bricks = []
+    for i, line in enumerate(fileinput.input()):
+        brick = tuple(list(map(int, p.split(","))) for p in line.rstrip("\n").split("~"))
+        brick = [list(map(int, p.split(","))) for p in line.rstrip("\n").split("~")]
+        brick.append(i)
+        bricks.append(brick)
+    return bricks
+
+
+def group_bricks_by_z(bricks):
+    bricks_by_z = defaultdict(list)
+    for brick in bricks:
+        p1, p2, _id = brick
+        z_min, z_max = min(p1[2], p2[2]), max(p1[2], p2[2])
+        for z in range(z_min, z_max + 1):
+            bricks_by_z[z].append(brick)
+    return bricks_by_z
+
+
+def extract_coordinate(bricks, axis):
+    az = [a for t in map(lambda b: (b[0][axis], b[1][axis]), bricks) for a in t]
+    a_min, a_max = min(az), max(az)
+    a_len = max(az) - min(az) + 1
+    return az, a_min, a_max, a_len
+
+
+def id2name(id):
+    return chr(id + ord('A'))
+
+def brick_name(brick):
+    return id2name(brick[2])
+
+def print_bricks_side(bricks, axis):
+    _ss, s_min, s_max, s_len = extract_coordinate(bricks, axis)
+    _zs, z_min, z_max, z_len = extract_coordinate(bricks, 2)
+    bricks_by_z = group_bricks_by_z(bricks)
+
+    # Print view S-axis
+    print(" " * (s_len//2) + ("x" if axis == 0 else "y") + " " * (s_len//2))
+    s_axis = []
+    for s in range(s_min, s_max + 1):
+        s_axis.append(str(s))
+    print("".join(s_axis))
+
+    for z in range(z_max, z_min - 1, -1):
+        line = []
+        for s in range(s_min, s_max + 1):
+            bricks_present = []
+            for brick in bricks_by_z[z]:
+                bs_min = min(brick[0][axis], brick[1][axis])
+                bs_max = max(brick[0][axis], brick[1][axis])
+                if bs_min <= s <= bs_max:
+                    bricks_present.append(brick[2])
+            match len(bricks_present):
+                case 0:
+                    line.append(SYM_EMPTY)
+                case 1:
+                    line.append(id2name(bricks_present[0]))
+                case _:
+                    line.append(SYM_HIDDEN)
+        line.append(f" {z}")
+        if z == z_len//2 + 1:
+            line.append(f" z")
+        print("".join(line))
+    print("-" * s_len + " 0")
+
+
+def print_bricks(bricks):
+    print_bricks_side(bricks, 0)
+    print("")
+    print_bricks_side(bricks, 1)
+
+def overlaps_xy(brick_a, brick_b):
+    (a_x1, a_y1, _a_z1), (a_x2, a_y2, _a_z2), _a_id = brick_a
+    (b_x1, b_y1, _b_z1), (b_x2, b_y2, _b_z2), _b_id = brick_b
+
+    overlap_x = a_x1 <= b_x1 <= a_x2 or b_x1 <= a_x1 <= b_x2
+    overlap_y = a_y1 <= b_y1 <= a_y2 or b_y1 <= a_y1 <= b_y2
+
+    return overlap_x and overlap_y
+
+def fall(bricks_by_z, brick):
+    (_x1, _y1, z1), (_x2, _y2, z2), _id = brick
+    z_min = min(z1, z2)
+    if z_min == 1:
+        return False
+
+    for brick_below in bricks_by_z[z_min - 1]:
+        if overlaps_xy(brick, brick_below):
+            return False
+
+    brick[0][2] -= 1
+    brick[1][2] -= 1
+    return True
+
+def settle_bricks(bricks):
+    for brick in sorted(bricks, key=lambda b: min(b[0][2], b[1][2])):
+        bricks_by_z = group_bricks_by_z(bricks)
+        while fall(bricks_by_z, brick):
+            pass
+
+def calc_brick_supported_by(bricks, bricks_by_z):
+    brick_supported_by = defaultdict(int) # brick_id -> int(nbr bricks it is supported by)
+    for brick in bricks:
+        (x1, y1, z1), (x2, y2, z2), id = brick
+        z_min = min(z1, z2)
+        for brick_below in bricks_by_z[z_min - 1]:
+            if overlaps_xy(brick, brick_below):
+                brick_supported_by[id] += 1
+    return brick_supported_by
+
+
+def disintegration_safe(bricks):
+    bricks_by_z = group_bricks_by_z(bricks)
+    brick_supported_by = calc_brick_supported_by(bricks, bricks_by_z)
+
+    safe_bricks = []
+    for brick in bricks:
+        (x1, y1, z1), (x2, y2, z2), id = brick
+        z_max = max(z1, z2)
+        safe = True
+        for brick_above in bricks_by_z[z_max + 1]:
+            if overlaps_xy(brick, brick_above) and brick_supported_by[brick_above[2]] == 1:
+                safe = False
+                break
+        if safe:
+            safe_bricks.append(brick)
+    return safe_bricks
+
+
+def main():
+    bricks = read_bricks()
+    # print_bricks(bricks)
+
+    settle_bricks(bricks)
+    # print("\n==== After settling:")
+    # print_bricks(bricks)
+
+    bricks_safe = disintegration_safe(bricks)
+    print(len(bricks_safe))
+
+if __name__ == '__main__':
+	main()
diff --git a/2023/22/part2.py b/2023/22/part2.py
@@ -0,0 +1,153 @@
+#!/usr/bin/env python3
+import fileinput
+from pprint import pprint
+from collections import defaultdict
+from copy import deepcopy
+import heapq
+
+SYM_EMPTY = "."
+SYM_HIDDEN = "?"
+
+def read_bricks():
+    bricks = []
+    for i, line in enumerate(fileinput.input()):
+        brick = tuple(list(map(int, p.split(","))) for p in line.rstrip("\n").split("~"))
+        brick = [list(map(int, p.split(","))) for p in line.rstrip("\n").split("~")]
+        brick.append(i)
+        bricks.append(brick)
+    return bricks
+
+
+def group_bricks_by_z(bricks):
+    bricks_by_z = defaultdict(list)
+    for brick in bricks:
+        p1, p2, _id = brick
+        z_min, z_max = min(p1[2], p2[2]), max(p1[2], p2[2])
+        for z in range(z_min, z_max + 1):
+            bricks_by_z[z].append(brick)
+    return bricks_by_z
+
+
+def extract_coordinate(bricks, axis):
+    az = [a for t in map(lambda b: (b[0][axis], b[1][axis]), bricks) for a in t]
+    a_min, a_max = min(az), max(az)
+    a_len = max(az) - min(az) + 1
+    return az, a_min, a_max, a_len
+
+
+def id2name(id):
+    return chr(id + ord('A'))
+
+def brick_name(brick):
+    return id2name(brick[2])
+
+def print_bricks_side(bricks, axis):
+    _ss, s_min, s_max, s_len = extract_coordinate(bricks, axis)
+    _zs, z_min, z_max, z_len = extract_coordinate(bricks, 2)
+    bricks_by_z = group_bricks_by_z(bricks)
+
+    # Print view S-axis
+    print(" " * (s_len//2) + ("x" if axis == 0 else "y") + " " * (s_len//2))
+    s_axis = []
+    for s in range(s_min, s_max + 1):
+        s_axis.append(str(s))
+    print("".join(s_axis))
+
+    for z in range(z_max, z_min - 1, -1):
+        line = []
+        for s in range(s_min, s_max + 1):
+            bricks_present = []
+            for brick in bricks_by_z[z]:
+                bs_min = min(brick[0][axis], brick[1][axis])
+                bs_max = max(brick[0][axis], brick[1][axis])
+                if bs_min <= s <= bs_max:
+                    bricks_present.append(brick[2])
+            match len(bricks_present):
+                case 0:
+                    line.append(SYM_EMPTY)
+                case 1:
+                    line.append(id2name(bricks_present[0]))
+                case _:
+                    line.append(SYM_HIDDEN)
+        line.append(f" {z}")
+        if z == z_len//2 + 1:
+            line.append(f" z")
+        print("".join(line))
+    print("-" * s_len + " 0")
+
+
+def print_bricks(bricks):
+    print_bricks_side(bricks, 0)
+    print("")
+    print_bricks_side(bricks, 1)
+
+def overlaps_xy(brick_a, brick_b):
+    (a_x1, a_y1, _a_z1), (a_x2, a_y2, _a_z2), _a_id = brick_a
+    (b_x1, b_y1, _b_z1), (b_x2, b_y2, _b_z2), _b_id = brick_b
+
+    overlap_x = a_x1 <= b_x1 <= a_x2 or b_x1 <= a_x1 <= b_x2
+    overlap_y = a_y1 <= b_y1 <= a_y2 or b_y1 <= a_y1 <= b_y2
+
+    return overlap_x and overlap_y
+
+def fall(bricks_by_z, brick):
+    (_x1, _y1, z1), (_x2, _y2, z2), _id = brick
+    z_min = min(z1, z2)
+    if z_min == 1:
+        return False
+
+    for brick_below in bricks_by_z[z_min - 1]:
+        if overlaps_xy(brick, brick_below):
+            return False
+
+    brick[0][2] -= 1
+    brick[1][2] -= 1
+    return True
+
+def settle_bricks(bricks):
+    for brick in sorted(bricks, key=lambda b: min(b[0][2], b[1][2])):
+        bricks_by_z = group_bricks_by_z(bricks)
+        while fall(bricks_by_z, brick):
+            pass
+
+def brick_supported_by(brick, fallen_bricks, bricks_by_z):
+    supported_by = 0
+    (x1, y1, z1), (x2, y2, z2), id = brick
+    z_min = min(z1, z2)
+    for brick_below in bricks_by_z[z_min - 1]:
+        if brick_below[2] not in fallen_bricks and overlaps_xy(brick, brick_below):
+            supported_by += 1
+
+    return supported_by
+
+def disintegration_falls(bricks_by_z, brick):
+    b_z_min = min(brick[0][2], brick[1][2])
+    fallen_bricks = set([brick[2]]) # brick IDs
+    falling = [(b_z_min, brick)]
+    while falling:
+        falling_brick = heapq.heappop(falling)[1]
+        (x1, y1, z1), (x2, y2, z2), id = falling_brick
+        fb_z_max = max(z1, z2)
+
+        for brick_above in bricks_by_z[fb_z_max + 1]:
+            if overlaps_xy(falling_brick, brick_above) and brick_supported_by(brick_above, fallen_bricks, bricks_by_z) == 0:
+                if brick_above[2] not in fallen_bricks:
+                    fallen_bricks.add(brick_above[2])
+                    ba_z_min = min(brick_above[0][2], brick_above[1][2])
+                    heapq.heappush(falling, (ba_z_min, brick_above))
+
+    return len(fallen_bricks) - 1
+
+
+def main():
+    bricks = read_bricks()
+    settle_bricks(bricks)
+    bricks_by_z = group_bricks_by_z(bricks)
+
+    falls = 0
+    for brick in bricks:
+        falls += disintegration_falls(bricks_by_z, brick)
+    print(falls)
+
+if __name__ == '__main__':
+	main()
diff --git a/tricks.md b/tricks.md
@@ -199,6 +199,8 @@ to get side-by-side comparison between expected (column 1) and actual (column 2)
 
 ## Misc
 * It's a good idea during development to output the state of the program in the same format as the puzzle description. This could be for example single lines of state, or to print every snapshot of the progress of some algorithm on a grid system. Having the same format as the puzzle description makes comparision with given examples easy!
+  * Examples: [2023/22](2023/22/part1.py), [2023/17](2023/17/part1.py)
+
 * Constraint solver
   * Is the problem too hard to solve? Let someone else do it: [Z3](https://github.com/Z3Prover/Z3).
   * Examples: [2018/10](2018/23/part2.rb)

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+[InternetShortcut]`
	`2`	`+URL = https://adventofcode.com/2023/day/22`