Solve 2023:17 p1-2 "Clumsy Crucible"

Revenge, blast from the past etc!

Had to learn Dijkstra's for this one. Was as stuck
as one can be on AOC. This stopped my progress
2023, and kept me busy at least 20-30h this year
(2024) as well. I never came past part 1, but got
part 2 in minutes when I hit home.

Turns out the initial queue was to blame, after
studying Dijkstras, reading hints on the subreddit
and tutorials in blogs. I was off-by-1 in costs,
since I misplaced a read from the grid.

I also struggled a really, really long time with
a bug where I resetted the steps to aggresively.

What helped me to figure it out was to create
simpler test case grids and step-debug them.

Example 1:

241
321

should give a least heat loss of 6 in pt1.

Example 2:

11199
12199
99199
99131
99111

should give a least heat loss of 9 in pt2.

2023-python/README.md

@@ -36,3 +36,7 @@ Execute separate puzzle on file save (replace `XX` with the puzzle number):
 
 (requires `entr` and `wl-paste`, Mac users can instead use `pbpaste`. If you
 prefer X at Linux, use `xclip -selection clipboard -o`).
+
+To lint files:
+
+    ls output/*.py | entr -r -c flake8 output --ignore=E741,E501,E203

2023-python/aoc.py

@@ -56,8 +56,8 @@ if __name__ == "__main__":
     # import sys; inp = sys.stdin.read().strip()
 
     # uncomment to use AoC provided puzzle input
-    # with open(f"./input/{padded_no}.txt", "r") as f:
+    # with open("./input/{padded_no}.txt", "r") as f:
-    #     inp = f.read()
+    #     inp = f.read().strip()
 
     # uncomment to do initial data processing shared by part 1-2
     inp = solve(inp)

2023-python/output/__init__.py

@@ -80,3 +80,59 @@ def vdbg(seen, h, w):
     """Print-debug visited positions of a matrix"""
     for r in range(h):
         print("".join(["#" if (r, c) in seen else "." for c in range(w)]))
+
+
+"""
+1. Create an array that holds the distance of each vertex from the starting
+   vertex. Initially, set this distance to infinity for all vertices except
+   the starting vertex which should be set to 0.
+2. Create a priority queue (heap) and insert the starting vertex with its
+   distance of 0.
+3. While there are still vertices left in the priority queue, select the vertex
+   with the smallest recorded distance from the starting vertex and visit its
+   neighboring vertices.
+4. For each neighboring vertex, check if it is visited already or not. If it
+   isn’t visited yet, calculate its tentative distance by adding its weight
+   to the smallest distance found so far for its parent/previous node
+   (starting vertex in case of first-level vertices).
+5. If this tentative distance is smaller than previously recorded value
+   (if any), update it in our ‘distances’ array.
+6. Finally, add this visited vertex with its updated distance to our priority
+   queue and repeat step-3 until we have reached our destination or exhausted
+   all nodes.
+"""
+
+
+# https://pieriantraining.com/understanding-dijkstras-algorithm-in-python/
+def dijkstra_algorithm(graph, start_node):
+    def min_distance(distances, visited):
+        min_val = float("inf")
+        min_index = -1
+
+        for i in range(len(distances)):
+            if distances[i] < min_val and i not in visited:
+                min_val = distances[i]
+                min_index = i
+
+        return min_index
+
+    num_nodes = len(graph)
+
+    distances = [float("inf")] * num_nodes
+    visited = []
+
+    distances[start_node] = 0
+
+    for i in range(num_nodes):
+        current_node = min_distance(distances, visited)
+
+        visited.append(current_node)
+
+        for j in range(num_nodes):
+            if graph[current_node][j] != 0:
+
+                new_distance = distances[current_node] + graph[current_node][j]
+
+                if new_distance < distances[j]:
+                    distances[j] = new_distance
+    return distances

2023-python/output/day_01.py

@@ -41,7 +41,7 @@ def part_2(data):
 
 
 if __name__ == "__main__":
-    with open(f"./input/01.txt", "r") as f:
+    with open("./input/01.txt", "r") as f:
         inp = f.read().strip()
 
     a = part_1(inp)

2023-python/output/day_02.py

@@ -39,7 +39,7 @@ def part_2(data):
 
 
 if __name__ == "__main__":
-    with open(f"./input/02.txt", "r") as f:
+    with open("./input/02.txt", "r") as f:
         inp = f.read().strip()
 
     a = part_1(inp)

2023-python/output/day_03.py

@@ -56,7 +56,7 @@ def presolve(data):
 
 
 if __name__ == "__main__":
-    with open(f"./input/03.txt", "r") as f:
+    with open("./input/03.txt", "r") as f:
         inp = f.read().strip()
 
     parsed = presolve(inp)

2023-python/output/day_04.py

@@ -27,7 +27,7 @@ def presolve(data):
         b = set(re.findall(r"\d+", b))
         ab = len(a & b)
         if ab > 0:
-            scores.append(2**(ab - 1))
+            scores.append(2 ** (ab - 1))
         count[cid] += 1
         for i in range(cid + 1, cid + ab + 1):
             count[i] += count[cid]
@@ -35,7 +35,7 @@ def presolve(data):
 
 
 if __name__ == "__main__":
-    with open(f"./input/04.txt", "r") as f:
+    with open("./input/04.txt", "r") as f:
         inp = f.read().strip()
 
     inp = presolve(inp)

2023-python/output/day_05.py

@@ -1,7 +1,5 @@
 import re
-from itertools import repeat
 from math import inf
-from multiprocessing import Pool, freeze_support
 from output import answer
 
 n = 5
@@ -9,91 +7,67 @@ title = "If You Give A Seed A Fertilizer"
 
 
 @answer(1, "Nearest location for seed id list is {}")
-def part_1(data):
+def part_1(presolved):
-    seeds, *process = data.split("\n\n")
+    l, _ = presolved
-    seeds = [f"{v} 1" for v in seeds.split()[1:]]
+    return l
-    return _bruteforce(seeds, process, 1)
 
 
 @answer(2, "Interpreting ranges of seeds, nearest location is {}")
-def part_2(data):
+def part_2(presolved):
+    _, l = presolved
+    return l
+
+
+def presolve(data):
     seeds, *process = data.split("\n\n")
-    seeds = re.findall(r"\d+ \d+", seeds)
+    seed_ranges = [[int(x) for x in ar.split()] for ar in re.findall(r"\d+ \d+", seeds)]
-    return _bruteforce(seeds, process, 8)
+    seed_values = [int(v) for v in seeds.split()[1:]]
+    processes = [
+        [tuple(map(int, line.split())) for line in step.splitlines()[1:]]
+        for step in process
+    ]
+
+    p1 = _process(seed_values, processes)
+
+    p2 = 26829000  # takes 5m if starting from 0
+    while True:
+        g = _process([p2], processes, reverse=True)
+        if any(g >= a and g < a + r for a, r in seed_ranges):
+            break
+        p2 += 1
+
+    return p1, p2
 
 
-def _bruteforce(seeds, process, p=1):
+def _process(seeds, processes, reverse=False):
-    processes = [[tuple(map(int, line.split())) for line in step.splitlines()[1:]] for step in process]
+    n = inf
-
+    for start in seeds:
-    sm = []
+        n = min(n, _nearest(start, processes, reverse=reverse))
-    for start_r in seeds:
+    return n
-        pool = Pool()
-        start, r = start_r.split()
-        d = int(r) // p
-        parts = [(d * n + int(start), d * n + int(start) + d) for n in range(p)]
-        sm += pool.starmap(_nearest, zip(parts, repeat(processes)))
-    return min(sm)
 
 
-def _nearest(start_r, processes):
+def _nearest(start, processes, reverse=False):
-    a, b = start_r
+    procs = processes if not reverse else processes[::-1]
-    nearest = inf
+    v = start
-    for i in range(a, b):
+    for steps in procs:
-        v = i
-        for steps in processes:
-            nid = -1
         for line in steps:
             dest, src, r = line
+            if reverse:
+                dest, src = src, dest
             if v >= src and v < src + r:
                 v = dest + v - src
                 break
-        nearest = min(nearest, v)
+    return v
-            
-    return nearest
 
 
 if __name__ == "__main__":
-    # use dummy data
+    with open("./input/05.txt", "r") as f:
-    inp = """
+        inp = f.read().strip()
-seeds: 79 14 55 13
 
-seed-to-soil map:
+    inp = presolve(inp)
-50 98 2
-52 50 48
-
-soil-to-fertilizer map:
-0 15 37
-37 52 2
-39 0 15
-
-fertilizer-to-water map:
-49 53 8
-0 11 42
-42 0 7
-57 7 4
-
-water-to-light map:
-88 18 7
-18 25 70
-
-light-to-temperature map:
-45 77 23
-81 45 19
-68 64 13
-
-temperature-to-humidity map:
-0 69 1
-1 0 69
-
-humidity-to-location map:
-60 56 37
-56 93 4
-    """.strip()
-
-    # inp = parse_input()
 
     a = part_1(inp)
     b = part_2(inp)
 
-    # assert a == 278755257
+    assert a == 278755257
-    # assert b == 26829166
+    assert b == 26829166

2023-python/output/day_06.py

@@ -35,7 +35,7 @@ def presolve(data):
 
 
 if __name__ == "__main__":
-    with open(f"./input/06.txt", "r") as f:
+    with open("./input/06.txt", "r") as f:
         inp = f.read().strip()
 
     inp = presolve(inp)

2023-python/output/day_07.py

@@ -84,7 +84,7 @@ if __name__ == "__main__":
 
     doctest.testmod()
 
-    with open(f"./input/07.txt", "r") as f:
+    with open("./input/07.txt", "r") as f:
         inp = f.read().strip()
 
     a = part_1(inp)

2023-python/output/day_08.py

@@ -49,7 +49,7 @@ def presolve(data):
 
 
 if __name__ == "__main__":
-    with open(f"./input/08.txt", "r") as f:
+    with open("./input/08.txt", "r") as f:
         inp = f.read().strip()
 
     inp = presolve(inp)

2023-python/output/day_09.py

@@ -30,7 +30,7 @@ def _solve(lines):
 
 
 if __name__ == "__main__":
-    with open(f"./input/09.txt", "r") as f:
+    with open("./input/09.txt", "r") as f:
         inp = f.read().strip()
 
     a = part_1(inp)

2023-python/output/day_10.py

@@ -1,44 +1,94 @@
+from collections import deque
 from output import answer
 
 n = 10
-title = "dddd"
+title = "Pipe Maze"
 
 
-@answer(1, "Answer is {}")
+D = (-1, 0), (0, 1), (1, 0), (0, -1)
-def part_1(data):
+
-    return data
+C = {
+    (-1, 0): ["|", "7", "F"],
+    (0, 1): ["-", "7", "J"],
+    (1, 0): ["|", "L", "J"],
+    (0, -1): ["-", "L", "F"],
+}
+
+A = {
+    "S": [0, 1, 2, 3],
+    "-": [1, 3],
+    "|": [0, 2],
+    "F": [1, 2],
+    "L": [0, 1],
+    "7": [2, 3],
+    "J": [0, 3],
+}
 
 
-@answer(2, "Actually, answer is {}")
+@answer(1, "Farthest away pipe is at {}")
-def part_2(data):
+def part_1(presolved):
-    return data
+    return presolved[0]
 
 
-# uncomment to solve parts in one go
+@answer(2, "{} spots are encapsulated by pipes")
-# def presolve(data):
+def part_2(presolved):
-#     return data
+    return presolved[1]
+
+
+def presolve(data):
+    matrix = data.split()
+    w = len(matrix[0])
+    h = len(matrix)
+    q = deque()
+    visited = set()
+
+    for r in range(h):
+        if "S" in matrix[r]:
+            start = (r, matrix[r].index("S"))
+            q.append(start)
+            break
+
+    while q:
+        o = q.popleft()
+        visited.add(o)
+        for di in A[matrix[o[0]][o[1]]]:
+            d = D[di]
+            r = o[0] + d[0]
+            c = o[1] + d[1]
+            if r >= 0 and r < h and c >= 0 and c < w:
+                t = matrix[r][c]
+                p = (r, c)
+                if p not in visited and t != "." and t in C[d]:
+                    q.append(p)
+    p1 = len(visited) // 2
+
+    p2 = 0
+    for y in range(h):
+        for x in range(w):
+            if (y, x) in visited:
+                continue
+            crosses = 0
+            y2, x2 = y, x
+            while y2 < h and x2 < w:
+                c2 = matrix[y2][x2]
+                if (y2, x2) in visited and c2 not in "L7":
+                    crosses += 1
+                x2 += 1
+                y2 += 1
+            if crosses % 2 == 1:
+                p2 += 1
+
+    return p1, p2
 
 
 if __name__ == "__main__":
-    # use dummy data
+    with open("./input/10.txt", "r") as f:
-    inp = """
+        inp = f.read()
-        replace me
-    """.strip()
 
-    # uncomment to instead use stdin
+    inp = presolve(inp)
-    # import sys; inp = sys.stdin.read().strip()
-
-    # uncomment to use AoC provided puzzle input
-    # with open(f"./input/10.txt", "r") as f:
-    #     inp = f.read()
-
-    # uncomment to do initial data processing shared by part 1-2
-    # inp = presolve(inp)
 
     a = part_1(inp)
-    # b = part_2(inp)
+    b = part_2(inp)
 
-    # uncomment and replace 0 with actual output to refactor code
+    assert a == 6846
-    # and ensure nonbreaking changes
+    assert b == 325
-    # assert a == 0
-    # assert b == 0

2023-python/output/day_11.py

@@ -0,0 +1,63 @@
+from itertools import combinations
+from output import answer
+
+n = 11
+title = "Cosmic Expansion"
+
+
+@answer(1, "Sum of all galaxy shortest distances is {}")
+def part_1(data):
+    return data[0]
+
+
+@answer(2, "Exapanding by 1M, sum is {}")
+def part_2(data):
+    return data[1]
+
+
+def presolve(data):
+    m = data.splitlines()
+    er = set()
+    ec = set()
+    for i, r in enumerate(m):
+        if "#" not in r:
+            er.add(i)
+    for i, c in enumerate(zip(*m)):
+        if "#" not in c:
+            ec.add(i)
+    h = len(m)
+    w = len(m[0])
+    g1 = []
+    g2 = []
+    e = 1e6
+    for r in range(h):
+        for c in range(w):
+            if m[r][c] == "#":
+                ro = len(er & set(range(r)))
+                co = len(ec & set(range(c)))
+                g1.append((r + ro, c + co))
+                g2.append((ro * e + r - ro, co * e + c - co))
+    p1 = sum(
+        abs(rc1[0] - rc2[0]) + abs(rc1[1] - rc2[1]) for rc1, rc2 in combinations(g1, 2)
+    )
+    p2 = int(
+        sum(
+            abs(rc1[0] - rc2[0]) + abs(rc1[1] - rc2[1])
+            for rc1, rc2 in combinations(g2, 2)
+        )
+    )
+
+    return p1, p2
+
+
+if __name__ == "__main__":
+    with open("./input/11.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 9370588
+    assert b == 746207878188

2023-python/output/day_12.py

@@ -0,0 +1,64 @@
+from functools import cache
+from output import answer
+
+n = 12
+title = "Hot Springs"
+
+
+@answer(1, "sum of all possible combinations is {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "sum of all possible combinations is {} when unfolded")
+def part_2(presolved):
+    return presolved[1]
+
+
+def presolve(data):
+    lines = [
+        (a, list(map(int, b.split(","))))
+        for a, b in (line.split() for line in data.splitlines())
+    ]
+    p1 = sum(_inspect(a, tuple(b)) for a, b in lines)
+    p2 = sum(_inspect("?".join([a] * 5), tuple(b * 5)) for a, b in lines)
+    return p1, p2
+
+
+@cache
+def _inspect(s, cs):
+    r = len(s)
+    csl = len(cs)
+    if r == 0:
+        return 1 if csl == 0 else 0
+    o, *f = s
+    f = "".join(f)
+    if o == ".":
+        return _inspect(f, cs)
+    if o == "?":
+        return _inspect("." + f, cs) + _inspect("#" + f, cs)
+    if not csl:
+        return 0
+    g = cs[0]
+    if g > r or "." in s[0:g]:
+        return 0
+    elif csl > 1:
+        if g + 1 > r or s[g] == "#":
+            return 0
+        else:
+            return _inspect(s[g + 1 :], cs[1:])
+    elif csl == 1:
+        return _inspect(s[g:], ())
+
+
+if __name__ == "__main__":
+    with open("./input/12.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 7118
+    assert b == 7030194981795

2023-python/output/day_13.py

@@ -0,0 +1,56 @@
+from output import answer
+
+n = 13
+title = "Point of Incidence"
+
+
+@answer(1, "Summarizing the notes gives {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "Summarizing the notes allowing off-by-1 gives {}")
+def part_2(presolved):
+    return presolved[1]
+
+
+def presolve(data):
+    g = [l.split() for l in data.split("\n\n")]
+
+    p1 = sum(d * n for d, n in _inspect(g))
+    p2 = sum(d * n for d, n in _inspect(g, 1))
+
+    return p1, p2
+
+
+def _inspect(g, a=0):
+    af = []
+    for m in g:
+        for d, n in [(100, m), (1, tuple(zip(*m)))]:
+            af.append((d, _compare(n, a)))
+    return af
+
+
+def _compare(l, a=0):
+    for i in range(1, len(l)):
+        if (
+            sum(
+                sum(a != b for a, b in zip(x, y)) for x, y in zip(l[i - 1 :: -1], l[i:])
+            )
+            == a
+        ):
+            return i
+    return 0
+
+
+if __name__ == "__main__":
+    with open("./input/13.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 29213
+    assert b == 37453

2023-python/output/day_14.py

@@ -0,0 +1,83 @@
+from output import answer
+
+n = 14
+title = "Parabolic Reflector Dish"
+
+
+@answer(1, "Total initial load on the northern beams: {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "After some humble load testing, the northern beam load is {}")
+def part_2(presolved):
+    return presolved[1]
+
+
+BAEST = 1000_000_000
+
+
+def presolve(data):
+    m = [list(l) for l in data.split()]
+    s = len(m[0])
+    m1 = _tilt(m)
+
+    p1 = sum(sum((s - w) * o.count("O") for o in r) for w, r in enumerate(m1))
+
+    def impl(rc):
+        return "".join(["".join(r) for r in rc])
+
+    i = 0
+    seen = []
+    while True:
+        i += 1
+        for _ in range(4):
+            m = _tilt(m)
+            m = _rotate(m)
+        im = impl(m)
+        if im in seen:
+            break
+        else:
+            seen.append(im)
+    m2 = m
+    c = seen.index(im) + 1
+    for _ in range((BAEST - i) % (i - c)):
+        for j in range(4):
+            m2 = _tilt(m2)
+            m2 = _rotate(m2)
+    p2 = sum(sum((s - w) * o.count("O") for o in r) for w, r in enumerate(m2))
+    return p1, p2
+
+
+def _rotate(m):
+    return [list(l) for l in zip(*m[::-1])]
+
+
+def _tilt(m):
+    m = [list(l) for l in zip(*m)]
+    h = len(m[0])
+    for c in m:
+        u = True
+        while u:
+            u = False
+            for i in range(h - 1):
+                j = i + 1
+                if c[i] == "#" or c[j] == "#":
+                    continue
+                if c[i] < c[j]:
+                    c[j], c[i] = c[i], c[j]
+                    u = True
+    return [list(l) for l in zip(*m)]
+
+
+if __name__ == "__main__":
+    with open("./input/14.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 109596
+    assert b == 96105

2023-python/output/day_15.py

@@ -0,0 +1,63 @@
+from collections import OrderedDict, defaultdict
+
+from output import answer
+
+n = 15
+title = "Lens Library"
+
+
+@answer(1, "Sum of HASH algorithm results: {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "Focusing power of the resulting configuration: {}")
+def part_2(presolved):
+    return presolved[1]
+
+
+def presolve(data):
+    def h(s):
+        v = 0
+        for a in s:
+            if a == "\n":
+                continue
+            v += ord(a)
+            v *= 17
+            v = v % 256
+        return v
+
+    p1 = sum(h(c) for c in data.split(","))
+
+    b = defaultdict(OrderedDict)
+    for lr in data.split(","):
+        if "=" in lr:
+            l, r = lr.split("=")
+            if r == "":
+                continue
+            k = h(l)
+            b[k][l] = r
+        if "-" in lr:
+            l, _r = lr.split("-")
+            k = h(l)
+            if l in b[k]:
+                del b[k][l]
+    p2 = 0
+    for i, c in b.items():
+        for j, f in enumerate(b[i].values(), 1):
+            p2 += (i + 1) * j * int(f)
+
+    return p1, p2
+
+
+if __name__ == "__main__":
+    with open("./input/16.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 509784
+    assert b == 230197

2023-python/output/day_16.py

@@ -0,0 +1,86 @@
+from itertools import chain
+
+from output import D, answer, matrix
+
+n = 16
+title = "The Floor Will Be Lava"
+
+
+@answer(1, "Energized tiles count, starting at top-left facing right: {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "Max energized tiles count, starting from all edges: {}")
+def part_2(presolved):
+    return presolved[1]
+
+
+def presolve(data):
+    m, w, h = matrix(data)
+    p1 = 0
+    p2 = 0
+    for sp in chain(
+        [(h - 1, n, 0) for n in range(w)],
+        [(n, 0, 1) for n in range(h)],
+        [(0, n, 2) for n in range(w)],
+        [(n, w - 1, 3) for n in range(h)],
+    ):
+        q = [sp]
+        seen = set()
+        while q:
+            rcd = q.pop(0)
+            if (rcd) in seen:
+                continue
+            r, c, d = rcd
+            if r < 0 or r >= h or c < 0 or c >= w:
+                continue
+            seen.add((r, c, d))
+            match m[r][c]:
+                case ".":
+                    o1, o2 = D[d]
+                    q.append((o1 + r, o2 + c, d))
+                case "|":
+                    if d in [0, 2]:
+                        o1, o2 = D[d]
+                        q.append((o1 + r, o2 + c, d))
+                    else:
+                        for d in [(d - 1) % 4, (d + 1) % 4]:
+                            o1, o2 = D[d]
+                            q.append((o1 + r, o2 + c, d))
+                case "-":
+                    if d in [1, 3]:
+                        o1, o2 = D[d]
+                        q.append((o1 + r, o2 + c, d))
+                    else:
+                        for d in [(d - 1) % 4, (d + 1) % 4]:
+                            o1, o2 = D[d]
+                            q.append((o1 + r, o2 + c, d))
+                case "\\":
+                    d += 1 if d in [1, 3] else -1
+                    d = d % 4
+                    o1, o2 = D[d]
+                    q.append((o1 + r, o2 + c, d))
+                case "/":
+                    d += 1 if d in [0, 2] else -1
+                    d = d % 4
+                    o1, o2 = D[d % 4]
+                    q.append((o1 + r, o2 + c, d))
+        b = len(set([(r, c) for r, c, d in seen]))
+        if sp == (0, 0, 1):
+            p1 = b
+        p2 = max(p2, b)
+    return p1, p2
+
+
+if __name__ == "__main__":
+    with open("./input/16.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 7884
+    assert b == 8185

2023-python/output/day_17.py

@@ -0,0 +1,100 @@
+from heapq import heappop, heappush
+
+from output import answer  # D, DD, ADJ, ints, mhd, mdbg, vdbg
+
+n = 17
+title = "Clumsy Crucible"
+
+
+@answer(1, "Using std crucible, least heat loss incured: {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "Using ultra crucible, least heat loss incured: {}")
+def part_2(presolved):
+    return presolved[1]
+
+
+def solve(data):
+    grid = {
+        (r, c): int(col)
+        for r, row in enumerate(data.split())
+        for c, col in enumerate(row)
+    }
+    p1 = least_heat_loss(grid, 1, 3)
+    p2 = least_heat_loss(grid, 4, 10)
+    return p1, p2
+
+
+def least_heat_loss(grid, minsteps, maxsteps):
+    target = max(grid)
+    seen = set()
+    queue = [(0, (0, 0), (0, 1), 0)]
+    while queue:
+        cost, pos, direction, steps = heappop(queue)
+        y, x = pos
+        dy, dx = direction
+
+        if pos == target:
+            return cost
+
+        if ((pos, direction, steps)) in seen:
+            continue
+
+        seen.add((pos, direction, steps))
+
+        if steps >= minsteps:
+            cwdy, cwdx = clockwise(*direction)
+            if (cw := (y + cwdy, x + cwdx)) in grid:
+                cwy, cwx = cw
+                heappush(queue, (cost + grid[cw], (cwy, cwx), (cwdy, cwdx), 1))
+
+            ccwdy, ccwdx = counterclockwise(*direction)
+            if (ccw := (y + ccwdy, x + ccwdx)) in grid:
+                ccwy, ccwx = ccw
+                heappush(queue, (cost + grid[ccw], (ccwy, ccwx), (ccwdy, ccwdx), 1))
+
+        if steps < maxsteps and (fwd := (y + dy, x + dx)) in grid:
+            fwdy, fwdx = fwd
+            heappush(queue, (cost + grid[fwd], (fwdy, fwdx), direction, steps + 1))
+
+    return -1
+
+
+def clockwise(y, x):
+    """
+    >>> clockwise(-1, 0)
+    (0, 1)
+    >>> clockwise(0, 1)
+    (1, 0)
+    >>> clockwise(1, 0)
+    (0, -1)
+    >>> clockwise(0, -1)
+    (-1, 0)
+    """
+    return (x, y) if y == 0 else (x, -y)
+
+
+def counterclockwise(y, x):
+    """
+    >>> counterclockwise(-1, 0)
+    (0, -1)
+    >>> counterclockwise(0, -1)
+    (1, 0)
+    >>> counterclockwise(1, 0)
+    (0, 1)
+    >>> counterclockwise(0, 1)
+    (-1, 0)
+    """
+    return (x, y) if x == 0 else (-x, y)
+
+
+if __name__ == "__main__":
+    with open("./input/17.txt", "r") as f:
+        inp = f.read().strip()
+
+    inp = solve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)