Poetry stuff.

src/holt59/aoc/2023/day1.py

@@ -0,0 +1,45 @@
+import sys
+
+lines = sys.stdin.read().splitlines()
+
+lookups_1 = {str(d): d for d in range(1, 10)}
+lookups_2 = lookups_1 | {
+    d: i + 1
+    for i, d in enumerate(
+        (
+            "one",
+            "two",
+            "three",
+            "four",
+            "five",
+            "six",
+            "seven",
+            "eight",
+            "nine",
+        )
+    )
+}
+
+
+def find_values(lookups: dict[str, int]) -> list[int]:
+    values: list[int] = []
+
+    for line in filter(bool, lines):
+        first_digit = min(
+            lookups,
+            key=lambda lookup: index
+            if (index := line.find(lookup)) >= 0
+            else len(line),
+        )
+        last_digit = max(
+            lookups,
+            key=lambda lookup: index if (index := line.rfind(lookup)) >= 0 else -1,
+        )
+
+        values.append(10 * lookups[first_digit] + lookups[last_digit])
+
+    return values
+
+
+print(f"answer 1 is {sum(find_values(lookups_1))}")
+print(f"answer 2 is {sum(find_values(lookups_2))}")

src/holt59/aoc/2023/day10.py

@@ -0,0 +1,100 @@
+import os
+import sys
+from typing import Literal, cast
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+
+Symbol = Literal["|", "-", "L", "J", "7", "F", ".", "S"]
+
+lines: list[list[Symbol]] = [
+    [cast(Symbol, symbol) for symbol in line] for line in sys.stdin.read().splitlines()
+]
+
+# find starting point
+si, sj = next(
+    (i, j)
+    for i in range(len(lines))
+    for j in range(len(lines[0]))
+    if lines[i][j] == "S"
+)
+
+# find one of the two outputs
+ni, nj = si, sj
+for ni, nj, chars in (
+    (si - 1, sj, "|7F"),
+    (si + 1, sj, "|LJ"),
+    (si, sj - 1, "-LF"),
+    (si, sj + 1, "-J7"),
+):
+    if lines[ni][nj] in chars:
+        break
+
+# part 1 - find the loop (re-used in part 2)
+loop = [(si, sj), (ni, nj)]
+while True:
+    pi, pj = loop[-2]
+    i, j = loop[-1]
+
+    sym = lines[i][j]
+
+    if sym == "|" and pi > i or sym in "JL" and pi == i:
+        i -= 1
+    elif sym == "|" and pi < i or sym in "7F" and pi == i:
+        i += 1
+    elif sym == "-" and pj > j or sym in "J7" and pj == j:
+        j -= 1
+    elif sym == "-" and pj < j or sym in "LF" and pj == j:
+        j += 1
+
+    if (i, j) == (si, sj):
+        break
+
+    loop.append((i, j))
+
+answer_1 = len(loop) // 2
+print(f"answer 1 is {answer_1}")
+
+# part 2
+
+# replace S by an appropriate character for the loop below
+di1, dj1 = loop[1][0] - loop[0][0], loop[1][1] - loop[0][1]
+di2, dj2 = loop[0][0] - loop[-1][0], loop[0][1] - loop[-1][1]
+mapping: dict[tuple[int, int], dict[tuple[int, int], Symbol]] = {
+    (0, 1): {(0, 1): "-", (-1, 0): "F", (1, 0): "L"},
+    (0, -1): {(0, -1): "-", (-1, 0): "7", (1, 0): "J"},
+    (1, 0): {(1, 0): "|", (0, 1): "7", (0, -1): "F"},
+    (-1, 0): {(-1, 0): "|", (0, -1): "L", (0, 1): "J"},
+}
+lines[si][sj] = mapping[di1, dj1][di2, dj2]
+
+# find the points inside the loop using an adaptation of ray casting for a discrete
+# grid (https://stackoverflow.com/a/218081/2666289)
+#
+# use a set for faster '... in loop' check
+#
+loop_s = set(loop)
+inside: set[tuple[int, int]] = set()
+for i in range(len(lines)):
+    cnt = 0
+    for j in range(len(lines[0])):
+        if (i, j) not in loop_s and cnt % 2 == 1:
+            inside.add((i, j))
+
+        if (i, j) in loop_s and lines[i][j] in "|LJ":
+            cnt += 1
+
+if VERBOSE:
+    for i in range(len(lines)):
+        for j in range(len(lines[0])):
+            if (i, j) == (si, sj):
+                print("\033[91mS\033[0m", end="")
+            elif (i, j) in loop:
+                print(lines[i][j], end="")
+            elif (i, j) in inside:
+                print("\033[92mI\033[0m", end="")
+            else:
+                print(".", end="")
+        print()
+
+answer_2 = len(inside)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day11.py

@@ -0,0 +1,41 @@
+import sys
+
+import numpy as np
+
+lines = sys.stdin.read().splitlines()
+
+data = np.array([[c == "#" for c in line] for line in lines])
+
+rows = {c for c in range(data.shape[0]) if not data[c, :].any()}
+columns = {c for c in range(data.shape[1]) if not data[:, c].any()}
+
+galaxies_y, galaxies_x = np.where(data)  # type: ignore
+
+
+def compute_total_distance(expansion: int) -> int:
+    distances: list[int] = []
+    for g1 in range(len(galaxies_y)):
+        x1, y1 = int(galaxies_x[g1]), int(galaxies_y[g1])
+        for g2 in range(g1 + 1, len(galaxies_y)):
+            x2, y2 = int(galaxies_x[g2]), int(galaxies_y[g2])
+
+            dx = sum(
+                1 + (expansion - 1) * (x in columns)
+                for x in range(min(x1, x2), max(x1, x2))
+            )
+            dy = sum(
+                1 + (expansion - 1) * (y in rows)
+                for y in range(min(y1, y2), max(y1, y2))
+            )
+
+            distances.append(dx + dy)
+    return sum(distances)
+
+
+# part 1
+answer_1 = compute_total_distance(2)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = compute_total_distance(1000000)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day12.py

@@ -0,0 +1,107 @@
+import os
+import sys
+from functools import lru_cache
+from typing import Iterable
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+
+
+@lru_cache
+def compute_fitting_arrangements(pattern: str, counts: tuple[int, ...]) -> int:
+    """
+    fn3p tries to fit ALL values in counts() inside the pattern.
+    """
+    # no pattern -> ok if nothing to fit, otherwise ko
+    if not pattern:
+        count = 1 if not counts else 0
+
+    # no count -> ok if pattern has no mandatory entry, else ko
+    elif not counts:
+        count = 1 if pattern.find("#") == -1 else 0
+
+    # cannot fit all values -> ko
+    elif len(pattern) < sum(counts) + len(counts) - 1:
+        count = 0
+
+    elif len(pattern) < counts[0]:
+        count = 0
+
+    else:
+        count = 0
+
+        if pattern[0] == "?":
+            count += compute_fitting_arrangements(pattern[1:], counts)
+
+        if len(pattern) == counts[0]:
+            count += 1
+
+        elif pattern[counts[0]] != "#":
+            count += compute_fitting_arrangements(pattern[counts[0] + 1 :], counts[1:])
+
+    return count
+
+
+@lru_cache
+def compute_possible_arrangements(
+    patterns: tuple[str, ...], counts: tuple[int, ...]
+) -> int:
+    if not patterns:
+        return 1 if not counts else 0
+
+    with_hash = sum(1 for p in patterns[1:] if p.find("#") >= 0)
+
+    if with_hash > len(counts):
+        return 0
+
+    to_fit = counts if with_hash == 0 else counts[:-with_hash]
+    remaining = () if with_hash == 0 else counts[-with_hash:]
+
+    if not to_fit:
+        if patterns[0].find("#") != -1:
+            return 0
+        return compute_possible_arrangements(patterns[1:], remaining)
+
+    elif patterns[0].find("#") != -1 and len(patterns[0]) < to_fit[0]:
+        return 0
+
+    elif patterns[0].find("?") == -1:
+        if len(patterns[0]) != to_fit[0]:
+            return 0
+        return compute_possible_arrangements(patterns[1:], counts[1:])
+
+    else:
+        return sum(
+            fp * compute_possible_arrangements(patterns[1:], to_fit[i:] + remaining)
+            for i in range(len(to_fit) + 1)
+            if (fp := compute_fitting_arrangements(patterns[0], to_fit[:i])) > 0
+        )
+
+
+def compute_all_possible_arrangements(lines: Iterable[str], repeat: int) -> int:
+    count = 0
+
+    if VERBOSE:
+        from tqdm import tqdm
+
+        lines = tqdm(lines)
+
+    for line in lines:
+        parts = line.split(" ")
+        count += compute_possible_arrangements(
+            tuple(filter(len, "?".join(parts[0] for _ in range(repeat)).split("."))),
+            tuple(int(c) for c in parts[1].split(",")) * repeat,
+        )
+
+    return count
+
+
+lines = sys.stdin.read().splitlines()
+
+
+# part 1
+answer_1 = compute_all_possible_arrangements(lines, 1)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = compute_all_possible_arrangements(lines, 5)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day13.py

@@ -0,0 +1,43 @@
+import sys
+from typing import Callable, Literal
+
+
+def split(block: list[str], axis: Literal[0, 1], count: int) -> int:
+    n_iter = len(block) if axis == 0 else len(block[0])
+    n_check = len(block) if axis == 1 else len(block[0])
+
+    at: Callable[[int, int], str] = (
+        (lambda i, j: block[i][j]) if axis == 0 else (lambda i, j: block[j][i])
+    )
+
+    for i in range(n_iter - 1):
+        size = min(i + 1, n_iter - i - 1)
+        if (
+            sum(
+                at(i - s, j) != at(i + 1 + s, j)
+                for s in range(0, size)
+                for j in range(n_check)
+            )
+            == count
+        ):
+            return i + 1
+
+    return 0
+
+
+blocks = [block.splitlines() for block in sys.stdin.read().split("\n\n")]
+
+
+# part 1
+answer_1 = sum(
+    split(block, axis=1, count=0) + 100 * split(block, axis=0, count=0)
+    for block in blocks
+)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = sum(
+    split(block, axis=1, count=1) + 100 * split(block, axis=0, count=1)
+    for block in blocks
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day14.py

@@ -0,0 +1,68 @@
+import sys
+from typing import TypeAlias
+
+RockGrid: TypeAlias = list[list[str]]
+
+rocks0 = [list(line) for line in sys.stdin.read().splitlines()]
+
+
+def slide_rocks_top(rocks: RockGrid) -> RockGrid:
+    top = [0 if c == "." else 1 for c in rocks[0]]
+    for row in range(1, len(rocks)):
+        for col in range(len(rocks[0])):
+            match rocks[row][col]:
+                case "O":
+                    if top[col] != row:
+                        rocks[top[col]][col] = "O"
+                        rocks[row][col] = "."
+                    top[col] = top[col] + 1
+                case "#":
+                    top[col] = row + 1
+                case _:
+                    pass
+    return rocks
+
+
+def cycle(rocks: RockGrid) -> RockGrid:
+    for _ in range(4):
+        rocks = slide_rocks_top(rocks)
+        rocks = [
+            [rocks[len(rocks) - j - 1][i] for j in range(len(rocks))]
+            for i in range(len(rocks[0]))
+        ]
+
+    return rocks
+
+
+rocks = slide_rocks_top([[c for c in r] for r in rocks0])
+
+# part 1
+answer_1 = sum(
+    (len(rocks) - i) * sum(1 for c in row if c == "O") for i, row in enumerate(rocks)
+)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+rocks = rocks0
+
+N = 1000000000
+cycles: list[RockGrid] = []
+i_cycle: int = -1
+for i_cycle in range(N):
+    rocks = cycle(rocks)
+
+    if any(rocks == c for c in cycles):
+        break
+
+    cycles.append([[c for c in r] for r in rocks])
+
+cycle_start = next(i for i in range(len(cycles)) if (rocks == cycles[i]))
+cycle_length = i_cycle - cycle_start
+
+ci = cycle_start + (N - cycle_start) % cycle_length - 1
+
+answer_2 = sum(
+    (len(rocks) - i) * sum(1 for c in row if c == "O")
+    for i, row in enumerate(cycles[ci])
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day15.py

@@ -0,0 +1,31 @@
+import sys
+from functools import reduce
+
+steps = sys.stdin.read().strip().split(",")
+
+
+def _hash(s: str) -> int:
+    return reduce(lambda v, u: ((v + ord(u)) * 17) % 256, s, 0)
+
+
+# part 1
+answer_1 = sum(map(_hash, steps))
+print(f"answer 1 is {answer_1}")
+
+# part 2
+boxes: list[dict[str, int]] = [{} for _ in range(256)]
+
+for step in steps:
+    if (i := step.find("=")) >= 0:
+        label, length = step[:i], int(step[i + 1 :])
+        boxes[_hash(label)][label] = length
+    else:
+        label = step[:-1]
+        boxes[_hash(label)].pop(label, None)
+
+answer_2 = sum(
+    i_box * i_lens * length
+    for i_box, box in enumerate(boxes, start=1)
+    for i_lens, length in enumerate(box.values(), start=1)
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day16.py

@@ -0,0 +1,110 @@
+import os
+import sys
+from typing import Literal, TypeAlias, cast
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+
+CellType: TypeAlias = Literal[".", "|", "-", "\\", "/"]
+Direction: TypeAlias = Literal["R", "L", "U", "D"]
+
+Mappings: dict[
+    CellType,
+    dict[
+        Direction,
+        tuple[tuple[tuple[int, int, Direction], ...], tuple[Direction, ...]],
+    ],
+] = {
+    ".": {
+        "R": (((0, +1, "R"),), ("R", "L")),
+        "L": (((0, -1, "L"),), ("R", "L")),
+        "U": (((-1, 0, "U"),), ("U", "D")),
+        "D": (((+1, 0, "D"),), ("U", "D")),
+    },
+    "-": {
+        "R": (((0, +1, "R"),), ("R", "L")),
+        "L": (((0, -1, "L"),), ("R", "L")),
+        "U": (((0, +1, "R"), (0, -1, "L")), ("U", "D")),
+        "D": (((0, +1, "R"), (0, -1, "L")), ("U", "D")),
+    },
+    "|": {
+        "U": (((-1, 0, "U"),), ("U", "D")),
+        "D": (((+1, 0, "D"),), ("U", "D")),
+        "R": (((-1, 0, "U"), (+1, 0, "D")), ("R", "L")),
+        "L": (((-1, 0, "U"), (+1, 0, "D")), ("R", "L")),
+    },
+    "/": {
+        "R": (((-1, 0, "U"),), ("R", "D")),
+        "L": (((+1, 0, "D"),), ("L", "U")),
+        "U": (((0, +1, "R"),), ("U", "L")),
+        "D": (((0, -1, "L"),), ("R", "D")),
+    },
+    "\\": {
+        "R": (((+1, 0, "D"),), ("R", "U")),
+        "L": (((-1, 0, "U"),), ("L", "D")),
+        "U": (((0, -1, "L"),), ("U", "R")),
+        "D": (((0, +1, "R"),), ("L", "D")),
+    },
+}
+
+
+def propagate(
+    layout: list[list[CellType]], start: tuple[int, int], direction: Direction
+) -> list[list[tuple[Direction, ...]]]:
+    n_rows, n_cols = len(layout), len(layout[0])
+
+    beams: list[list[tuple[Direction, ...]]] = [
+        [() for _ in range(len(layout[0]))] for _ in range(len(layout))
+    ]
+
+    queue = [(start, direction)]
+
+    while queue:
+        (row, col), direction = queue.pop()
+
+        if (
+            row not in range(0, n_rows)
+            or col not in range(0, n_cols)
+            or direction in beams[row][col]
+        ):
+            continue
+
+        moves, update = Mappings[layout[row][col]][direction]
+
+        beams[row][col] += update
+
+        for move in moves:
+            queue.append(((row + move[0], col + move[1]), move[2]))
+
+    return beams
+
+
+layout: list[list[CellType]] = [
+    [cast(CellType, col) for col in row] for row in sys.stdin.read().splitlines()
+]
+
+
+beams = propagate(layout, (0, 0), "R")
+
+if VERBOSE:
+    print("\n".join(["".join("#" if col else "." for col in row) for row in beams]))
+
+# part 1
+answer_1 = sum(sum(map(bool, row)) for row in beams)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+n_rows, n_cols = len(layout), len(layout[0])
+cases: list[tuple[tuple[int, int], Direction]] = []
+
+for row in range(n_rows):
+    cases.append(((row, 0), "R"))
+    cases.append(((row, n_cols - 1), "L"))
+for col in range(n_cols):
+    cases.append(((0, col), "D"))
+    cases.append(((n_rows - 1, col), "U"))
+
+answer_2 = max(
+    sum(sum(map(bool, row)) for row in propagate(layout, start, direction))
+    for start, direction in cases
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day17.py

@@ -0,0 +1,233 @@
+from __future__ import annotations
+
+import heapq
+import os
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+from typing import Literal, TypeAlias
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+
+Direction: TypeAlias = Literal[">", "<", "^", "v"]
+
+
+@dataclass(frozen=True, order=True)
+class Label:
+    row: int
+    col: int
+
+    direction: Direction
+    count: int
+
+    parent: Label | None = None
+
+
+# mappings from direction to row shift / col shift / opposite direction
+MAPPINGS: dict[Direction, tuple[int, int, Direction]] = {
+    ">": (0, +1, "<"),
+    "<": (0, -1, ">"),
+    "v": (+1, 0, "^"),
+    "^": (-1, 0, "v"),
+}
+
+
+def print_shortest_path(
+    grid: list[list[int]],
+    target: tuple[int, int],
+    per_cell: dict[tuple[int, int], list[tuple[Label, int]]],
+):
+    assert len(per_cell[target]) == 1
+    label = per_cell[target][0][0]
+
+    path: list[Label] = []
+    while True:
+        path.insert(0, label)
+        if label.parent is None:
+            break
+        label = label.parent
+
+    p_grid = [[str(c) for c in r] for r in grid]
+
+    for i in range(len(grid)):
+        for j in range(len(grid[0])):
+            if per_cell[i, j]:
+                p_grid[i][j] = f"\033[94m{grid[i][j]}\033[0m"
+
+    prev_label = path[0]
+    for label in path[1:]:
+        for r in range(
+            min(prev_label.row, label.row), max(prev_label.row, label.row) + 1
+        ):
+            for c in range(
+                min(prev_label.col, label.col),
+                max(prev_label.col, label.col) + 1,
+            ):
+                if (r, c) != (prev_label.row, prev_label.col):
+                    p_grid[r][c] = f"\033[93m{grid[r][c]}\033[0m"
+
+        p_grid[label.row][label.col] = f"\033[91m{grid[label.row][label.col]}\033[0m"
+
+        prev_label = label
+
+    p_grid[0][0] = f"\033[92m{grid[0][0]}\033[0m"
+
+    print("\n".join("".join(row) for row in p_grid))
+
+
+def shortest_many_paths(grid: list[list[int]]) -> dict[tuple[int, int], int]:
+    n_rows, n_cols = len(grid), len(grid[0])
+
+    visited: dict[tuple[int, int], tuple[Label, int]] = {}
+
+    queue: list[tuple[int, Label]] = [
+        (0, Label(row=n_rows - 1, col=n_cols - 1, direction="^", count=0))
+    ]
+
+    while queue and len(visited) != n_rows * n_cols:
+        distance, label = heapq.heappop(queue)
+
+        if (label.row, label.col) in visited:
+            continue
+
+        visited[label.row, label.col] = (label, distance)
+
+        for direction, (c_row, c_col, i_direction) in MAPPINGS.items():
+            if label.direction == i_direction:
+                continue
+            else:
+                row, col = (label.row + c_row, label.col + c_col)
+
+            # exclude labels outside the grid or with too many moves in the same
+            # direction
+            if row not in range(0, n_rows) or col not in range(0, n_cols):
+                continue
+
+            heapq.heappush(
+                queue,
+                (
+                    distance
+                    + sum(
+                        grid[r][c]
+                        for r in range(min(row, label.row), max(row, label.row) + 1)
+                        for c in range(min(col, label.col), max(col, label.col) + 1)
+                    )
+                    - grid[row][col],
+                    Label(
+                        row=row,
+                        col=col,
+                        direction=direction,
+                        count=0,
+                        parent=label,
+                    ),
+                ),
+            )
+
+    return {(r, c): visited[r, c][1] for r in range(n_rows) for c in range(n_cols)}
+
+
+def shortest_path(
+    grid: list[list[int]],
+    min_straight: int,
+    max_straight: int,
+    lower_bounds: dict[tuple[int, int], int],
+) -> int:
+    n_rows, n_cols = len(grid), len(grid[0])
+
+    target = (len(grid) - 1, len(grid[0]) - 1)
+
+    # for each tuple (row, col, direction, count), the associated label when visited
+    visited: dict[tuple[int, int, str, int], Label] = {}
+
+    # list of all visited labels for a cell (with associated distance)
+    per_cell: dict[tuple[int, int], list[tuple[Label, int]]] = defaultdict(list)
+
+    # need to add two start labels, otherwise one of the two possible direction will
+    # not be possible
+    queue: list[tuple[int, int, Label]] = [
+        (lower_bounds[0, 0], 0, Label(row=0, col=0, direction="^", count=0)),
+        (lower_bounds[0, 0], 0, Label(row=0, col=0, direction="<", count=0)),
+    ]
+
+    while queue:
+        _, distance, label = heapq.heappop(queue)
+
+        if (label.row, label.col, label.direction, label.count) in visited:
+            continue
+
+        visited[label.row, label.col, label.direction, label.count] = label
+        per_cell[label.row, label.col].append((label, distance))
+
+        if (label.row, label.col) == target:
+            break
+
+        for direction, (c_row, c_col, i_direction) in MAPPINGS.items():
+            # cannot move in the opposite direction
+            if label.direction == i_direction:
+                continue
+
+            # other direction, move 'min_straight' in the new direction
+            elif label.direction != direction:
+                row, col, count = (
+                    label.row + min_straight * c_row,
+                    label.col + min_straight * c_col,
+                    min_straight,
+                )
+
+            # same direction, too many count
+            elif label.count == max_straight:
+                continue
+
+            # same direction, keep going and increment count
+            else:
+                row, col, count = (
+                    label.row + c_row,
+                    label.col + c_col,
+                    label.count + 1,
+                )
+            # exclude labels outside the grid or with too many moves in the same
+            # direction
+            if row not in range(0, n_rows) or col not in range(0, n_cols):
+                continue
+
+            distance_to = (
+                distance
+                + sum(
+                    grid[r][c]
+                    for r in range(min(row, label.row), max(row, label.row) + 1)
+                    for c in range(min(col, label.col), max(col, label.col) + 1)
+                )
+                - grid[label.row][label.col]
+            )
+
+            heapq.heappush(
+                queue,
+                (
+                    distance_to + lower_bounds[row, col],
+                    distance_to,
+                    Label(
+                        row=row,
+                        col=col,
+                        direction=direction,
+                        count=count,
+                        parent=label,
+                    ),
+                ),
+            )
+
+    if VERBOSE:
+        print_shortest_path(grid, target, per_cell)
+
+    return per_cell[target][0][1]
+
+
+data = [[int(c) for c in r] for r in sys.stdin.read().splitlines()]
+estimates = shortest_many_paths(data)
+
+# part 1
+answer_1 = shortest_path(data, 1, 3, lower_bounds=estimates)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = shortest_path(data, 4, 10, lower_bounds=estimates)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day18.py

@@ -0,0 +1,54 @@
+import sys
+from typing import Literal, TypeAlias, cast
+
+Direction: TypeAlias = Literal["R", "L", "U", "D"]
+
+DIRECTIONS: list[Direction] = ["R", "D", "L", "U"]
+MOVES: dict[Direction, tuple[int, int]] = {
+    "R": (0, +1),
+    "L": (0, -1),
+    "U": (-1, 0),
+    "D": (+1, 0),
+}
+
+
+def area(corners: list[tuple[int, int]], perimeter: int) -> int:
+    area = abs(
+        sum(c0[0] * c1[1] - c0[1] * c1[0] for c0, c1 in zip(corners, corners[1::])) // 2
+    )
+    return 1 + area - perimeter // 2 + perimeter
+
+
+def polygon(values: list[tuple[Direction, int]]) -> tuple[list[tuple[int, int]], int]:
+    perimeter = 0
+    corners: list[tuple[int, int]] = [(0, 0)]
+    for direction, amount in values:
+        perimeter += amount
+        corners.append(
+            (
+                corners[-1][0] + amount * MOVES[direction][0],
+                corners[-1][1] + amount * MOVES[direction][1],
+            )
+        )
+    return corners, perimeter
+
+
+lines = sys.stdin.read().splitlines()
+
+
+# part 1
+answer_1 = area(
+    *polygon([(cast(Direction, (p := line.split())[0]), int(p[1])) for line in lines])
+)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = area(
+    *polygon(
+        [
+            (DIRECTIONS[int((h := line.split()[-1])[-2])], int(h[2:-2], 16))
+            for line in lines
+        ]
+    )
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day19.py

@@ -0,0 +1,132 @@
+import logging
+import operator
+import os
+import sys
+from math import prod
+from typing import Literal, TypeAlias, cast
+
+VERBOSE = os.getenv("AOC_VERBOSE") == "True"
+
+logging.basicConfig(level=logging.INFO if VERBOSE else logging.WARNING)
+
+Category: TypeAlias = Literal["x", "m", "a", "s"]
+Part: TypeAlias = dict[Category, int]
+PartWithBounds: TypeAlias = dict[Category, tuple[int, int]]
+
+OPERATORS = {"<": operator.lt, ">": operator.gt}
+
+# None if there is no check (last entry), otherwise (category, sense, value)
+Check: TypeAlias = tuple[Category, Literal["<", ">"], int] | None
+
+# workflow as a list of check, in specified order, with target
+Workflow: TypeAlias = list[tuple[Check, str]]
+
+
+def accept(workflows: dict[str, Workflow], part: Part) -> bool:
+    workflow = "in"
+    decision: bool | None = None
+
+    while decision is None:
+        for check, target in workflows[workflow]:
+            ok = check is None
+            if check is not None:
+                category, sense, value = check
+                ok = OPERATORS[sense](part[category], value)
+
+            if ok:
+                if target in workflows:
+                    workflow = target
+                else:
+                    decision = target == "A"
+                break
+
+    return decision
+
+
+def propagate(workflows: dict[str, Workflow], start: PartWithBounds) -> int:
+    def transfer_or_accept(
+        target: str, meta: PartWithBounds, queue: list[tuple[PartWithBounds, str]]
+    ) -> int:
+        if target in workflows:
+            logging.info(f"  transfer to {target}")
+            queue.append((meta, target))
+            return 0
+        elif target == "A":
+            logging.info("  accepted")
+            return prod((high - low + 1) for low, high in meta.values())
+        else:
+            logging.info("  rejected")
+            return 0
+
+    accepted = 0
+    queue: list[tuple[PartWithBounds, str]] = [(start, "in")]
+
+    while queue:
+        meta, workflow = queue.pop()
+        logging.info(f"{workflow}: {meta}")
+        for check, target in workflows[workflow]:
+            if check is None:
+                accepted += transfer_or_accept(target, meta, queue)
+                continue
+
+            category, sense, value = check
+            bounds, op = meta[category], OPERATORS[sense]
+
+            logging.info(f"  splitting {meta} into {category} {sense} {value}")
+
+            if not op(bounds[0], value) and not op(bounds[1], value):
+                logging.info("  reject, always false")
+                continue
+
+            if op(meta[category][0], value) and op(meta[category][1], value):
+                logging.info("  accept, always true")
+                accepted += transfer_or_accept(target, meta, queue)
+                break
+
+            meta2 = meta.copy()
+            if sense == "<":
+                meta2[category] = (meta[category][0], value - 1)
+                meta[category] = (value, meta[category][1])
+            else:
+                meta2[category] = (value + 1, meta[category][1])
+                meta[category] = (meta[category][0], value)
+            logging.info(f"  split {meta2} ({target}), {meta}")
+
+            accepted += transfer_or_accept(target, meta2, queue)
+
+    return accepted
+
+
+workflows_s, parts_s = sys.stdin.read().strip().split("\n\n")
+
+workflows: dict[str, Workflow] = {}
+for workflow_s in workflows_s.split("\n"):
+    name, block_s = workflow_s.split("{")
+    workflows[name] = []
+
+    for block in block_s[:-1].split(","):
+        check: Check
+        if (i := block.find(":")) >= 0:
+            check, target = (
+                cast(Category, block[0]),
+                cast(Literal["<", ">"], block[1]),
+                int(block[2:i]),
+            ), block[i + 1 :]
+        else:
+            check, target = None, block
+        workflows[name].append((check, target))
+
+# part 1
+parts: list[Part] = [
+    {cast(Category, s[0]): int(s[2:]) for s in part_s[1:-1].split(",")}
+    for part_s in parts_s.split("\n")
+]
+answer_1 = sum(sum(part.values()) for part in parts if accept(workflows, part))
+print(f"answer 1 is {answer_1}")
+
+
+# part 2
+answer_2 = propagate(
+    workflows, {cast(Category, c): (1, 4000) for c in ["x", "m", "a", "s"]}
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day2.py

@@ -0,0 +1,43 @@
+import math
+import sys
+from typing import Literal, TypeAlias, cast
+
+CubeType: TypeAlias = Literal["red", "blue", "green"]
+
+MAX_CUBES: dict[CubeType, int] = {"red": 12, "green": 13, "blue": 14}
+
+# parse games
+lines = sys.stdin.read().splitlines()
+games: dict[int, list[dict[CubeType, int]]] = {}
+for line in filter(bool, lines):
+    id_part, sets_part = line.split(":")
+
+    games[int(id_part.split(" ")[-1])] = [
+        {
+            cast(CubeType, s[1]): int(s[0])
+            for cube_draw in cube_set_s.strip().split(", ")
+            if (s := cube_draw.split(" "))
+        }
+        for cube_set_s in sets_part.strip().split(";")
+    ]
+
+# part 1
+answer_1 = sum(
+    id
+    for id, set_of_cubes in games.items()
+    if all(
+        n_cubes <= MAX_CUBES[cube]
+        for cube_set in set_of_cubes
+        for cube, n_cubes in cube_set.items()
+    )
+)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = sum(
+    math.prod(
+        max(cube_set.get(cube, 0) for cube_set in set_of_cubes) for cube in MAX_CUBES
+    )
+    for set_of_cubes in games.values()
+)
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day20.py

@@ -0,0 +1,13 @@
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+answer_1 = ...
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = ...
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day21.py

@@ -0,0 +1,13 @@
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+answer_1 = ...
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = ...
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day22.py

@@ -0,0 +1,13 @@
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+answer_1 = ...
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = ...
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day23.py

@@ -0,0 +1,13 @@
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+answer_1 = ...
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = ...
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day24.py

@@ -0,0 +1,13 @@
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+answer_1 = ...
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = ...
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day25.py

@@ -0,0 +1,13 @@
+import sys
+from collections import defaultdict
+from dataclasses import dataclass
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+answer_1 = ...
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = ...
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day3.py

@@ -0,0 +1,53 @@
+import string
+import sys
+from collections import defaultdict
+
+NOT_A_SYMBOL = "." + string.digits
+
+lines = sys.stdin.read().splitlines()
+
+values: list[int] = []
+gears: dict[tuple[int, int], list[int]] = defaultdict(list)
+
+for i, line in enumerate(lines):
+    j = 0
+    while j < len(line):
+        # skip everything until a digit is found (start of a number)
+        if line[j] not in string.digits:
+            j += 1
+            continue
+
+        # extract the range of the number and its value
+        k = j + 1
+        while k < len(line) and line[k] in string.digits:
+            k += 1
+
+        value = int(line[j:k])
+
+        # lookup around the number if there is a symbol - we go through the number
+        # itself but that should not matter since it only contains digits
+        found = False
+        for i2 in range(max(0, i - 1), min(i + 1, len(lines) - 1) + 1):
+            for j2 in range(max(0, j - 1), min(k, len(line) - 1) + 1):
+                assert i2 >= 0 and i2 < len(lines)
+                assert j2 >= 0 and j2 < len(line)
+
+                if lines[i2][j2] not in NOT_A_SYMBOL:
+                    found = True
+
+                    if lines[i2][j2] == "*":
+                        gears[i2, j2].append(value)
+
+        if found:
+            values.append(value)
+
+        # continue starting from the end of the number
+        j = k
+
+# part 1
+answer_1 = sum(values)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = sum(v1 * v2 for v1, v2 in filter(lambda vs: len(vs) == 2, gears.values()))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day4.py

@@ -0,0 +1,41 @@
+import sys
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class Card:
+    id: int
+    numbers: list[int]
+    values: list[int]
+
+
+lines = sys.stdin.read().splitlines()
+
+cards: list[Card] = []
+for line in lines:
+    id_part, e_part = line.split(":")
+    numbers_s, values_s = e_part.split("|")
+    cards.append(
+        Card(
+            id=int(id_part.split()[1]),
+            numbers=[int(v.strip()) for v in numbers_s.strip().split()],
+            values=[int(v.strip()) for v in values_s.strip().split()],
+        )
+    )
+
+winnings = [sum(1 for n in card.values if n in card.numbers) for card in cards]
+
+# part 1
+answer_1 = sum(2 ** (winning - 1) for winning in winnings if winning > 0)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+card2cards = {i: list(range(i + 1, i + w + 1)) for i, w in enumerate(winnings)}
+card2values = {i: 0 for i in range(len(cards))}
+
+for i in range(len(cards)):
+    card2values[i] += 1
+    for j in card2cards[i]:
+        card2values[j] += card2values[i]
+
+print(f"answer 2 is {sum(card2values.values())}")

src/holt59/aoc/2023/day5.py

@@ -0,0 +1,129 @@
+import sys
+from typing import Sequence
+
+MAP_ORDER = [
+    "seed",
+    "soil",
+    "fertilizer",
+    "water",
+    "light",
+    "temperature",
+    "humidity",
+    "location",
+]
+
+lines = sys.stdin.read().splitlines()
+
+# mappings from one category to another, each list contains
+# ranges stored as (source, target, length), ordered by start and
+# completed to have no "hole"
+maps: dict[tuple[str, str], list[tuple[int, int, int]]] = {}
+
+# parsing
+index = 2
+while index < len(lines):
+    p1, _, p2 = lines[index].split()[0].split("-")
+
+    # extract the existing ranges from the file - we store as (source, target, length)
+    # whereas the file is in order (target, source, length)
+    index += 1
+    values: list[tuple[int, int, int]] = []
+    while index < len(lines) and lines[index]:
+        n1, n2, n3 = lines[index].split()
+        values.append((int(n2), int(n1), int(n3)))
+        index += 1
+
+    # sort by source value
+    values.sort()
+
+    # add a 'fake' interval starting at 0 if missing
+    if values[0][0] != 0:
+        values.insert(0, (0, 0, values[0][0]))
+
+    # fill gaps between intervals
+    for i in range(len(values) - 1):
+        next_start = values[i + 1][0]
+        end = values[i][0] + values[i][2]
+        if next_start != end:
+            values.insert(
+                i + 1,
+                (end, end, next_start - end),
+            )
+
+    # add an interval covering values up to at least 2**32 at the end
+    last_start, _, last_length = values[-1]
+    values.append((last_start + last_length, last_start + last_length, 2**32))
+
+    assert all(v1[0] + v1[2] == v2[0] for v1, v2 in zip(values[:-1], values[1:]))
+    assert values[0][0] == 0
+    assert values[-1][0] + values[-1][-1] >= 2**32
+
+    maps[p1, p2] = values
+    index += 1
+
+
+def find_range(
+    values: tuple[int, int], map: list[tuple[int, int, int]]
+) -> list[tuple[int, int]]:
+    """
+    Given an input range, use the given mapping to find the corresponding list of
+    ranges in the target domain.
+    """
+    r_start, r_length = values
+    ranges: list[tuple[int, int]] = []
+
+    # find index of the first and last intervals in map that overlaps the input
+    # interval
+    index_start, index_end = -1, -1
+
+    for index_start, (start, _, length) in enumerate(map):
+        if start <= r_start and start + length > r_start:
+            break
+
+    for index_end, (start, _, length) in enumerate(
+        map[index_start:], start=index_start
+    ):
+        if r_start + r_length >= start and r_start + r_length < start + length:
+            break
+
+    assert index_start >= 0 and index_end >= 0
+
+    # special case if one interval contains everything
+    if index_start == index_end:
+        start, target, length = map[index_start]
+        ranges.append((target + r_start - start, r_length))
+    else:
+        # add the start interval part
+        start, target, length = map[index_start]
+        ranges.append((target + r_start - start, start + length - r_start))
+
+        # add all intervals between the first and last (excluding both)
+        index = index_start + 1
+        while index < index_end:
+            start, target, length = map[index]
+            ranges.append((target, length))
+            index += 1
+
+        # add the last interval
+        start, target, length = map[index_end]
+        ranges.append((target, r_start + r_length - start))
+
+    return ranges
+
+
+def find_location_ranges(seeds: Sequence[tuple[int, int]]) -> Sequence[tuple[int, int]]:
+    for map1, map2 in zip(MAP_ORDER[:-1], MAP_ORDER[1:]):
+        seeds = [s2 for s1 in seeds for s2 in find_range(s1, maps[map1, map2])]
+    return seeds
+
+
+# part 1 - use find_range() with range of length 1
+seeds_p1 = [(int(s), 1) for s in lines[0].split(":")[1].strip().split()]
+answer_1 = min(start for start, _ in find_location_ranges(seeds_p1))
+print(f"answer 1 is {answer_1}")
+
+# # part 2
+parts = lines[0].split(":")[1].strip().split()
+seeds_p2 = [(int(s), int(e)) for s, e in zip(parts[::2], parts[1::2])]
+answer_2 = min(start for start, _ in find_location_ranges(seeds_p2))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day6.py

@@ -0,0 +1,47 @@
+import math
+import sys
+
+
+def extreme_times_to_beat(time: int, distance: int) -> tuple[int, int]:
+    # formula (T = total time, D = target distance)
+    # - speed(t) = t,
+    # - distance(t) = (T - t) * speed(t)
+    # - distance(t) > D
+    #   <=> (T - t) * t > D
+    #   <=> -t^2 + T * t - D >= 0
+
+    a, b, c = -1, time, -distance
+    d = b * b - 4 * a * c
+
+    t1 = math.ceil(-(b - math.sqrt(d)) / (2 * a))
+    t2 = math.floor(-(b + math.sqrt(d)) / (2 * a))
+
+    if (time - t1) * t1 == distance:
+        t1 += 1
+
+    if (time - t2) * t2 == distance:
+        t2 -= 1
+
+    return t1, t2
+
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+times = list(map(int, lines[0].split()[1:]))
+distances = list(map(int, lines[1].split()[1:]))
+answer_1 = math.prod(
+    t2 - t1 + 1
+    for t1, t2 in (
+        extreme_times_to_beat(time, distance)
+        for time, distance in zip(times, distances)
+    )
+)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+time = int(lines[0].split(":")[1].strip().replace(" ", ""))
+distance = int(lines[1].split(":")[1].strip().replace(" ", ""))
+t1, t2 = extreme_times_to_beat(time, distance)
+answer_2 = t2 - t1 + 1
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day7.py

@@ -0,0 +1,49 @@
+import sys
+from collections import Counter, defaultdict
+
+
+class HandTypes:
+    HIGH_CARD = 0
+    ONE_PAIR = 1
+    TWO_PAIR = 2
+    THREE_OF_A_KIND = 3
+    FULL_HOUSE = 4
+    FOUR_OF_A_KIND = 5
+    FIVE_OF_A_KIND = 6
+
+
+# mapping from number of different cards + highest count of card to the hand type
+LEN_LAST_TO_TYPE: dict[int, dict[int, int]] = {
+    1: defaultdict(lambda: HandTypes.FIVE_OF_A_KIND),
+    2: defaultdict(lambda: HandTypes.FULL_HOUSE, {4: HandTypes.FOUR_OF_A_KIND}),
+    3: defaultdict(lambda: HandTypes.TWO_PAIR, {3: HandTypes.THREE_OF_A_KIND}),
+    4: defaultdict(lambda: HandTypes.ONE_PAIR),
+    5: defaultdict(lambda: HandTypes.HIGH_CARD),
+}
+
+
+def extract_key(hand: str, values: dict[str, int], joker: str = "0") -> tuple[int, ...]:
+    # get count of each cards, in increasing count - the 'or' part handles the JJJJJ
+    # case when joker is True
+    cnt = sorted(Counter(hand.replace(joker, "")).values()) or [0]
+
+    return (LEN_LAST_TO_TYPE[len(cnt)][cnt[-1] + hand.count(joker)],) + tuple(
+        values[c] for c in hand
+    )
+
+
+lines = sys.stdin.read().splitlines()
+cards = [(t[0], int(t[1])) for line in lines if (t := line.split())]
+
+
+# part 1
+values = {card: value for value, card in enumerate("23456789TJQKA")}
+cards.sort(key=lambda cv: extract_key(cv[0], values=values))
+answer_1 = sum(rank * value for rank, (_, value) in enumerate(cards, start=1))
+print(f"answer 1 is {answer_1}")
+
+# part 2
+values = {card: value for value, card in enumerate("J23456789TQKA")}
+cards.sort(key=lambda cv: extract_key(cv[0], values=values, joker="J"))
+answer_2 = sum(rank * value for rank, (_, value) in enumerate(cards, start=1))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day8.py

@@ -0,0 +1,29 @@
+import itertools
+import math
+import sys
+
+lines = sys.stdin.read().splitlines()
+
+sequence = lines[0]
+nodes = {
+    p[0]: {d: n for d, n in zip("LR", p[1].strip("()").split(", "))}
+    for line in lines[2:]
+    if (p := line.split(" = "))
+}
+
+
+def path(start: str):
+    path = [start]
+    it_seq = iter(itertools.cycle(sequence))
+    while not path[-1].endswith("Z"):
+        path.append(nodes[path[-1]][next(it_seq)])
+    return path
+
+
+# part 1
+answer_1 = len(path(next(node for node in nodes if node.endswith("A")))) - 1
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = math.lcm(*(len(path(node)) - 1 for node in nodes if node.endswith("A")))
+print(f"answer 2 is {answer_2}")

src/holt59/aoc/2023/day9.py

@@ -0,0 +1,29 @@
+import sys
+
+lines = sys.stdin.read().splitlines()
+
+data = [[int(c) for c in line.split()] for line in lines]
+
+right_values: list[int] = []
+left_values: list[int] = []
+for values in data:
+    diffs = [values]
+    while any(d != 0 for d in diffs[-1]):
+        diffs.append([rhs - lhs for lhs, rhs in zip(diffs[-1][:-1], diffs[-1][1:])])
+
+    rhs: list[int] = [0]
+    lhs: list[int] = [0]
+    for cx in range(len(diffs) - 1):
+        rhs.append(diffs[-cx - 2][-1] + rhs[cx])
+        lhs.append(diffs[-cx - 2][0] - lhs[cx])
+
+    right_values.append(rhs[-1])
+    left_values.append(lhs[-1])
+
+# part 1
+answer_1 = sum(right_values)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+answer_2 = sum(left_values)
+print(f"answer 2 is {answer_2}")