Try an interactive version of this dialog: Sign up at solve.it.com, click Upload, and pass this URL.

Note: 10

Start time: 1:06

Code: 9 ()

from fastcore.utils import *

Code: 60 ()

from aocd import get_data
inp = get_data(year=2025, day=10)
len(inp), len(inp.splitlines()), len(inp.splitlines()[0]), inp[:100]

Output: 172

(17427,
 165,
 191,
 '[.##....#..] (0,1,3,4,5,6,7,8,9) (0,1,2,4,5,6,7,8,9) (0,1,2,4,6,7,9) (1,2,3,5,7,8,9) (1,3,8) (7) (3,')

Code: 219 ()

samp = """[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}
[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}
[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}"""

Note: 1,234 ()

The manual describes one machine per line. Each line contains a single indicator light diagram in [square brackets], one or more button wiring schematics in (parentheses), and joltage requirements in {curly braces}.

To start a machine, its indicator lights must match those shown in the diagram, where . means off and # means on. The machine has the number of indicator lights shown, but its indicator lights are all initially off.

So, an indicator light diagram like [.##.] means that the machine has four indicator lights which are initially off and that the goal is to simultaneously configure the first light to be off, the second light to be on, the third to be on, and the fourth to be off.

You can toggle the state of indicator lights by pushing any of the listed buttons. Each button lists which indicator lights it toggles, where 0 means the first light, 1 means the second light, and so on. When you push a button, each listed indicator light either turns on (if it was off) or turns off (if it was on). You have to push each button an integer number of times; there's no such thing as "0.5 presses" (nor can you push a button a negative number of times).

So, a button wiring schematic like (0,3,4) means that each time you push that button, the first, fourth, and fifth indicator lights would all toggle between on and off. If the indicator lights were [#.....], pushing the button would change them to be [...##.] instead.

Because none of the machines are running, the joltage requirements are irrelevant and can be safely ignored.

You can push each button as many times as you like. However, to save on time, you will need to determine the fewest total presses required to correctly configure all indicator lights for all machines in your list.

There are a few ways to correctly configure the first machine:

[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7} You could press the first three buttons once each, a total of 3 button presses. You could press (1,3) once, (2,3) once, and (0,1) twice, a total of 4 button presses. You could press all of the buttons except (1,3) once each, a total of 5 button presses. However, the fewest button presses required is 2. One way to do this is by pressing the last two buttons ((0,2) and (0,1)) once each.

The second machine can be configured with as few as 3 button presses:

[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2} One way to achieve this is by pressing the last three buttons ((0,4), (0,1,2), and (1,2,3,4)) once each.

The third machine has a total of six indicator lights that need to be configured correctly:

[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5} The fewest presses required to correctly configure it is 2; one way to do this is by pressing buttons (0,3,4) and (0,1,2,4,5) once each.

So, the fewest button presses required to correctly configure the indicator lights on all of the machines is 2 + 3 + 2 = 7.

Analyze each machine's indicator light diagram and button wiring schematics. What is the fewest button presses required to correctly configure the indicator lights on all of the machines?

Code: 10 ()

lines = samp.splitlines()
lines

Output: 265

['[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}',
 '[...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2}',
 '[.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5}']

Prompt: 346

This feels like those frustrating puzzles in Skyrim haha. I think there are mathy names for this, but I don't know them. Which is going to make today a challenge! For the sample, I think we can probably get away with searching all 1-button, 2-button, 3-button... sequences but I doubt this is the case for the input.

Thinking more:

We want the #s to be on, this requires that we have an odd number of presses of buttons containing those numbers. We want the dots to be off, which requires that they show up an even number of times. We could use 1 bit per light and toggle as we go, so we could probably get very efficient. We can also use this to prune search: if we pick a button that turns on one that needs to end up off, we can only consider buttons that reverse that change as the next step (since order doesn't matter). And we don't need to consider pushing any button twice (since that undoes it!). So actually the max we need to search the number of lights, right?

(How am I doing so far?)

Assistant: 456

You're doing great! You've identified several key insights:

  1. It's a system of linear equations over GF(2) (the field with two elements, 0 and 1). Each light needs to be toggled an odd or even number of times, and since toggling twice = no toggle, we only care about each button being pressed 0 or 1 times (mod 2).

  2. Order doesn't matter - absolutely right! Pressing button A then B is the same as B then A.

  3. Pressing a button twice cancels out - so we only need to consider 0 or 1 presses of each button.

This means for each machine, you have at most 2^(number of buttons) possible combinations to check, but you only need to find if ANY combination produces the target pattern. This is actually a classic Gaussian elimination over GF(2) problem!

However, your pruning idea is interesting but might be tricky to implement correctly. The cleaner approach is to think of it as:

  • Each button is a column vector (which lights it toggles)
  • You want a linear combination of these vectors (over GF(2)) that equals your target pattern
  • Find the minimum number of vectors needed

For the sample, brute force should work fine. For the real input, you might need to be smarter. Want to try implementing a brute force solution first to see if it's fast enough, or would you like to explore the linear algebra approach?

Note: 10

Let's see how big the inputs are

Code: 58 ()

max_n = 0
for l in inp.splitlines():
    s = l.split(" ")[0][1:-1]
    max_n = max(max_n, len(s))
max_n

Output: 16

10

Code: 60 ()

max_n = 0
for l in inp.splitlines():
    s = l.split("{")[0][:-1].split(',')
    max_n = max(max_n, len(s))
max_n

Output: 16

61

Note: 40

OK! We can totally search 1024 options, but not 2^61 (61 buttons, but max 10 lights)

Code: 28 ()

lights = [l.split(" ")[0][1:-1] for l in lines]
lights

Output: 60

['.##.', '...#.', '.###.#']

Code: 46 ()

# All the tuples in brackets, using regex
btns = [re.findall(r'\([^)]+\)', l) for l in lines]
btns

Output: 324

[['(3)', '(1,3)', '(2)', '(2,3)', '(0,2)', '(0,1)'],
 ['(0,2,3,4)', '(2,3)', '(0,4)', '(0,1,2)', '(1,2,3,4)'],
 ['(0,1,2,3,4)', '(0,3,4)', '(0,1,2,4,5)', '(1,2)']]

Code: 64 ()

# '(1,3)' -> [1, 3]
btns = [[list(map(int, b[1:-1].split(','))) for b in line] for line in btns]
btns

Output: 196

[[[3], [1, 3], [2], [2, 3], [0, 2], [0, 1]],
 [[0, 2, 3, 4], [2, 3], [0, 4], [0, 1, 2], [1, 2, 3, 4]],
 [[0, 1, 2, 3, 4], [0, 3, 4], [0, 1, 2, 4, 5], [1, 2]]]

Note: 192

Hmm actually I said we only need to search every button once, but 2^61 is way too much. I could make this a 'shortest path in a graph' thing where each possible state (max 1024) is a node, and for all the buttons we add edges from the each state to whatever the new state will be. Then we can use our old fried networkx to find the shortest path from start (0) to end state. I'll name the nodes by interpreting the #s as 1s and the .s as 0s in a binary number.

Let's try it on the sample data.

Code: 67 ()

def s_to_n(s):
    b = s.replace(".", "0").replace("#", "1")
    return int(b, 2)

light_nodes = [s_to_n(l) for l in lights]
light_nodes

Output: 25

[6, 2, 29]

Code: 7 ()

import networkx as nx

Code: 27 ()

G = nx.DiGraph()
for n in light_nodes: G.add_node(n)

Code: 15 ()

for b in btns:
    print(b)

Output: 195

[[3], [1, 3], [2], [2, 3], [0, 2], [0, 1]]
[[0, 2, 3, 4], [2, 3], [0, 4], [0, 1, 2], [1, 2, 3, 4]]
[[0, 1, 2, 3, 4], [0, 3, 4], [0, 1, 2, 4, 5], [1, 2]]

Note: 18

Oh, wait I want to make a graph per line.

Code: 30 ()

ln = light_nodes[0]
bs = btns[0]
ln, bs # First line

Output: 63

(6, [[3], [1, 3], [2], [2, 3], [0, 2], [0, 1]])

Code: 118 ()

G = nx.DiGraph()
max_n = 2**6 # Use 2**10 for inp
for n in range(max_n): G.add_node(n)
for btn in bs:
    for n in range(max_n):
        nn = n
        for i in btn:
            nn ^= (1 << i)
        G.add_edge(n, nn, btn=btn)

Prompt: 15

How do I get the shortest path with nx?

Assistant: 159

You can use nx.shortest_path(G, source, target) which returns the path, or nx.shortest_path_length(G, source, target) which just gives you the number of edges.

In your case, you'd want something like:

Copied!
nx.shortest_path_length(G, source=0, target=ln)

Since you start at state 0 (all lights off) and want to reach state ln (the target configuration).

Does that make sense for what you're trying to do?

Code: 22 ()

nx.shortest_path_length(G, source=0, target=ln)

Output: 16

2

Prompt: 10

How do I get the buttons?

Assistant: 166

You can use nx.shortest_path(G, source=0, target=ln) to get the actual path (the sequence of nodes/states), and then look at the edge attributes between consecutive nodes.

Something like:

Copied!
path = nx.shortest_path(G, source=0, target=ln)
for i in range(len(path)-1):
    edge_data = G[path[i]][path[i+1]]
    print(edge_data['btn'])

This will show you which button was pressed at each step. Does that help?

Code: 67 ()

path = nx.shortest_path(G, source=0, target=ln)
for i in range(len(path)-1):
    edge_data = G[path[i]][path[i+1]]
    print(edge_data['btn'])

Output: 31

[2, 3]
[1, 3]

Note: 18

(I don't need this but who knows about part 2!)

Prompt: 33

OK tidy this up into a build_graph function and a solve function using the code above please

Assistant: 235

Here's a clean version:

Copied!
def build_graph(lights, btns):
    max_n = 2**len(lights)
    G = nx.DiGraph()
    for n in range(max_n): 
        G.add_node(n)
    for btn in btns:
        for n in range(max_n):
            nn = n
            for i in btn:
                nn ^= (1 << i)
            G.add_edge(n, nn, btn=btn)
    return G

def solve(lights, btns):
    target = s_to_n(lights)
    G = build_graph(lights, btns)
    return nx.shortest_path_length(G, source=0, target=target)

Want to test it on your sample data?

Code: 220 ()

def build_graph(lights, btns):
    max_n = 2**len(lights)
    G = nx.DiGraph()
    for n in range(max_n): 
        G.add_node(n)
    for btn in btns:
        for n in range(max_n):
            nn = n
            for i in btn:
                nn ^= (1 << (len(lights) - 1 - i))
            G.add_edge(n, nn, btn=btn)
    return G

def solve(lights, btns):
    target = s_to_n(lights)
    G = build_graph(lights, btns)
    return nx.shortest_path_length(G, source=0, target=target)

Code: 54 ()

# Do this for all in samp and sum
res = 0
for l, b in zip(lights, btns):
    res += solve(l, b)
res

Output: 16

7

Prompt: 6

What went wrong?

Assistant: 244

The second machine can't reach its target state from the starting state! This means there's no combination of button presses that will get you to the desired configuration.

Looking at your sample data, the second line is [...#.] with buttons [[0, 2, 3, 4], [2, 3], [0, 4], [0, 1, 2], [1, 2, 3, 4]]. The problem statement says this should be solvable in 3 button presses, so something must be wrong with how we're building the graph or interpreting the data.

Can you check: what does lights[1] and btns[1] show? And what does s_to_n(lights[1]) give you?

Code: 13 ()

lights[1], btns[1]

Output: 97

('...#.', [[0, 2, 3, 4], [2, 3], [0, 4], [0, 1, 2], [1, 2, 3, 4]])

Code: 12 ()

s_to_n(lights[1])

Output: 16

2

Prompt: 1

Assistant: 222

Ah, I think I see the bug! The button indices refer to lights from the left (0 = first/leftmost light), but when we do 1 << i, we're setting bits from the right.

For a 5-light system like ...#.:

  • Light index 3 (the #) is the 4th from the left
  • But 1 << 3 sets bit 3, which is the 4th from the right

We need to flip the bit indexing. Try changing the toggle line in build_graph to:

Copied!
nn ^= (1 << (len(lights) - 1 - i))

Does that make sense?

Note: 16

AAAAH I see.

OK now for inp:

Code: 145 ()

lines = inp.splitlines()
lights = [l.split(" ")[0][1:-1] for l in lines]
btns = [re.findall(r'\([^)]+\)', l) for l in lines]
btns = [[list(map(int, b[1:-1].split(','))) for b in line] for line in btns]
res = 0
for l, b in zip(lights, btns):
    res += solve(l, b)
res

Output: 16

441

Note: 6

Part 2

Note: 1,120

All of the machines are starting to come online! Now, it's time to worry about the joltage requirements.

Each machine needs to be configured to exactly the specified joltage levels to function properly. Below the buttons on each machine is a big lever that you can use to switch the buttons from configuring the indicator lights to increasing the joltage levels. (Ignore the indicator light diagrams.)

The machines each have a set of numeric counters tracking its joltage levels, one counter per joltage requirement. The counters are all initially set to zero.

So, joltage requirements like {3,5,4,7} mean that the machine has four counters which are initially 0 and that the goal is to simultaneously configure the first counter to be 3, the second counter to be 5, the third to be 4, and the fourth to be 7.

The button wiring schematics are still relevant: in this new joltage configuration mode, each button now indicates which counters it affects, where 0 means the first counter, 1 means the second counter, and so on. When you push a button, each listed counter is increased by 1.

So, a button wiring schematic like (1,3) means that each time you push that button, the second and fourth counters would each increase by 1. If the current joltage levels were {0,1,2,3}, pushing the button would change them to be {0,2,2,4}.

You can push each button as many times as you like. However, your finger is getting sore from all the button pushing, and so you will need to determine the fewest total presses required to correctly configure each machine's joltage level counters to match the specified joltage requirements.

Consider again the example from before:

[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7} [...#.] (0,2,3,4) (2,3) (0,4) (0,1,2) (1,2,3,4) {7,5,12,7,2} [.###.#] (0,1,2,3,4) (0,3,4) (0,1,2,4,5) (1,2) {10,11,11,5,10,5} Configuring the first machine's counters requires a minimum of 10 button presses. One way to do this is by pressing (3) once, (1,3) three times, (2,3) three times, (0,2) once, and (0,1) twice.

Configuring the second machine's counters requires a minimum of 12 button presses. One way to do this is by pressing (0,2,3,4) twice, (2,3) five times, and (0,1,2) five times.

Configuring the third machine's counters requires a minimum of 11 button presses. One way to do this is by pressing (0,1,2,3,4) five times, (0,1,2,4,5) five times, and (1,2) once.

So, the fewest button presses required to correctly configure the joltage level counters on all of the machines is 10 + 12 + 11 = 33.

Analyze each machine's joltage requirements and button wiring schematics. What is the fewest button presses required to correctly configure the joltage level counters on all of the machines?

Note: 40

OK, so, each button now increments the joltage by 1 for all covered counters. We can't UNDO / decrease.

Note: 81

Since each push increments by 1, the max number of pushes we need to search is, I suppose, the sum of the joltage targets (since worst case a button only increases one counter by one). Let's check the max values to see what we're dealing with.

Prompt: 1

Assistant: 172

Nice work on part 1!

For part 2, this is now a different type of problem - instead of toggling (mod 2), you're doing regular addition where each button can be pressed multiple times and you need to reach exact target values.

This is a system of linear equations over the integers (not mod 2 anymore). You want to find non-negative integer solutions that minimize the total number of button presses.

What's your intuition about how to approach this? Should we check what the max joltage values look like first to see if brute force is feasible?

Prompt: 66

Yeah I can see the simultaneous equations part of this, and I guess there are probably libraries that handle this... I'm wondering if there's a way that doesn't require knowing that/how other people already silved this type of problem.

Assistant: 226

Good instinct! Let's think about it from first principles.

One approach: you could try a greedy strategy. For each counter that needs the highest value, find which button affects it and press that button that many times. But this might overshoot other counters...

Another thought: what if you work backwards? Start by figuring out which counters need the most presses, and see if you can find buttons that "efficiently" hit multiple high-value counters at once.

Or, since the search space might not be too huge (depending on the max joltage values), you could try a search algorithm - maybe BFS or dynamic programming?

What do you think? Should we first check what the actual joltage values look like in your input to see what we're dealing with?

Prompt: 15

Yeah give me code to see what we're dealing with

Assistant: 202

Copied!
jolts = [l.split("{")[1].split("}")[0] for l in lines]
jolts = [[int(x) for x in j.split(',')] for j in jolts]

max_jolt = max(max(j) for j in jolts)
sum_jolt = max(sum(j) for j in jolts)
print(f"Max single joltage: {max_jolt}")
print(f"Max sum per machine: {sum_jolt}")

This will show you the largest individual joltage value and the largest total joltage needed for any single machine. That'll help you decide if brute force is feasible.

Code: 145 ()

jolts = [l.split("{")[1].split("}")[0] for l in lines]
jolts = [[int(x) for x in j.split(',')] for j in jolts]

max_jolt = max(max(j) for j in jolts)
sum_jolt = max(sum(j) for j in jolts)
print(f"Max single joltage: {max_jolt}")
print(f"Max sum per machine: {sum_jolt}")

Output: 40

Max single joltage: 275
Max sum per machine: 2137

Prompt: 117

I guess we could try:

  • rank buttons based on whether they inc the largest counter, then second largest, then ...
  • Press the top one until any other buttons are 'filled'
  • Then carry on that way

But this greedy approach seems unlikely to find the optimal solution.

Ah well, time to learn! Teach me about dynamic programming in this context without spoiling the solution too quickly

Assistant: 238

Great question! Dynamic programming is all about breaking a problem into overlapping subproblems and storing solutions to avoid recomputation.

The classic analogy is the coin change problem: given coins of certain denominations, what's the minimum number of coins to make a target value?

Here, you can think of each button as a "coin" that adds a specific pattern to your counters. You want the minimum number of "coins" (button presses) to reach your target joltage levels.

For 1D coin change, you'd build up a table: dp[v] = minimum coins to reach value v. You start with dp[0] = 0 and fill in the rest.

How might you extend this idea to multiple counters? What would your "state" be?

Prompt: 270

Hmm so if I had, say, 1 cent and 5 cent coins I'd put dp[1]=1, dp[5]=5. Then for all combos of non-0 values in the table, I'd fill in dp[v1+v2]=dp[v1]+dp[v2] - or rather, min(dp[v1]+dp[v2], dp[v1+v2]) since there might be multiple ways to get it and we want the lowest. OK, I think I see how that works for one. Neat!

For our case with multiple counters, we could have a multi-dimensional array as our table. The only problem is size - things could get big quick. Although we can exclude anything that goes over any of the counters. Can you give me code to check how big our multi-dim table could be and tell me if I'm on the right track?

Assistant: 166

You're on the right track! Let's check the state space size:

Copied!
from math import prod
for i, j in enumerate(jolts[:5]):  # First 5 machines
    size = prod(x+1 for x in j)
    print(f"Machine {i}: {len(j)} counters, state space: {size:,}")

This will show you the product of (target+1) for each counter - that's how many cells your multi-dimensional table would need. Try it and let's see if it's feasible!

Code: 85 ()

from math import prod
for i, j in enumerate(jolts[:5]):  # First 5 machines
    size = prod(x+1 for x in j)
    print(f"Machine {i}: {len(j)} counters, state space: {size:,}")

Output: 198

Machine 0: 10 counters, state space: 195,523,926,097,500,000
Machine 1: 9 counters, state space: 73,950,110,872,805,376,000
Machine 2: 9 counters, state space: 113,732,317,439,769,600
Machine 3: 10 counters, state space: 287,756,768,225,203,200
Machine 4: 10 counters, state space: 6,508,532,067,840,000

Prompt: 7

Womp womp.

Assistant: 267

Ha! Yeah, that's not going to work. Quadrillions of states is a bit much. 😅

So we need a smarter approach. A few directions to consider:

  1. Meet in the middle - split the buttons into two halves, enumerate all reachable states from each half, then find combinations that sum to the target
  2. BFS from 0 - instead of pre-building the whole table, only explore states you can actually reach (might still be too many though)
  3. Linear algebra - this really is a system of linear equations: you want to find non-negative integers x₁, x₂, ... (number of times to press each button) such that the button effects sum to your target

Want to explore any of these? Or check how many buttons each machine has - that might suggest which approach is feasible?

Prompt: 36

Let's do 3, which sounds like it's mostly going to be knowing syntax of an existing library. Over to you.

Assistant: 261

Alright! For solving systems of linear equations with non-negative integer solutions, you can use linear programming with integer constraints (this is called "integer linear programming" or ILP).

Python has a library called scipy.optimize with a function linprog, but for integer constraints you'll want something like pulp or scipy.optimize.milp (mixed integer linear programming).

The basic setup:

  • Each button press count is a variable (must be non-negative integer)
  • Each counter gives you one equation (sum of button effects = target joltage)
  • Objective: minimize the total number of button presses

Want to try setting this up? Start by checking if you have pulp available (import pulp), or we can use scipy.optimize.milp if you prefer. Which would you like to try?

Code: 9 ()

from scipy.optimize import milp

Code: 4 ()

milp??

Output: 12,120

Copied!
def milp(c, *, integrality=None, bounds=None, constraints=None, options=None):
    r"""
    Mixed-integer linear programming

    Solves problems of the following form:

    .. math::

        \min_x \ & c^T x \\
        \mbox{such that} \ & b_l \leq A x \leq b_u,\\
        & l \leq x \leq u, \\
        & x_i \in \mathbb{Z}, i \in X_i

    where :math:`x` is a vector of decision variables;
    :math:`c`, :math:`b_l`, :math:`b_u`, :math:`l`, and :math:`u` are vectors;
    :math:`A` is a matrix, and :math:`X_i` is the set of indices of
    decision variables that must be integral. (In this context, a
    variable that can assume only integer values is said to be "integral";
    it has an "integrality" constraint.)

    Alternatively, that's:

    minimize::

        c @ x

    such that::

        b_l <= A @ x <= b_u
        l <= x <= u
        Specified elements of x must be integers

    By default, ``l = 0`` and ``u = np.inf`` unless specified with
    ``bounds``.

    Parameters
    ----------
    c : 1D dense array_like
        The coefficients of the linear objective function to be minimized.
        `c` is converted to a double precision array before the problem is
        solved.
    integrality : 1D dense array_like, optional
        Indicates the type of integrality constraint on each decision variable.

        ``0`` : Continuous variable; no integrality constraint.

        ``1`` : Integer variable; decision variable must be an integer
        within `bounds`.

        ``2`` : Semi-continuous variable; decision variable must be within
        `bounds` or take value ``0``.

        ``3`` : Semi-integer variable; decision variable must be an integer
        within `bounds` or take value ``0``.

        By default, all variables are continuous. `integrality` is converted
        to an array of integers before the problem is solved.

    bounds : scipy.optimize.Bounds, optional
        Bounds on the decision variables. Lower and upper bounds are converted
        to double precision arrays before the problem is solved. The
        ``keep_feasible`` parameter of the `Bounds` object is ignored. If
        not specified, all decision variables are constrained to be
        non-negative.
    constraints : sequence of scipy.optimize.LinearConstraint, optional
        Linear constraints of the optimization problem. Arguments may be
        one of the following:

        1. A single `LinearConstraint` object
        2. A single tuple that can be converted to a `LinearConstraint` object
           as ``LinearConstraint(*constraints)``
        3. A sequence composed entirely of objects of type 1. and 2.

        Before the problem is solved, all values are converted to double
        precision, and the matrices of constraint coefficients are converted to
        instances of `scipy.sparse.csc_array`. The ``keep_feasible`` parameter
        of `LinearConstraint` objects is ignored.
    options : dict, optional
        A dictionary of solver options. The following keys are recognized.

        disp : bool (default: ``False``)
            Set to ``True`` if indicators of optimization status are to be
            printed to the console during optimization.
        node_limit : int, optional
            The maximum number of nodes (linear program relaxations) to solve
            before stopping. Default is no maximum number of nodes.
        presolve : bool (default: ``True``)
            Presolve attempts to identify trivial infeasibilities,
            identify trivial unboundedness, and simplify the problem before
            sending it to the main solver.
        time_limit : float, optional
            The maximum number of seconds allotted to solve the problem.
            Default is no time limit.
        mip_rel_gap : float, optional
            Termination criterion for MIP solver: solver will terminate when
            the gap between the primal objective value and the dual objective
            bound, scaled by the primal objective value, is <= mip_rel_gap.

    Returns
    -------
    res : OptimizeResult
        An instance of :class:`scipy.optimize.OptimizeResult`. The object
        is guaranteed to have the following attributes.

        status : int
            An integer representing the exit status of the algorithm.

            ``0`` : Optimal solution found.

            ``1`` : Iteration or time limit reached.

            ``2`` : Problem is infeasible.

            ``3`` : Problem is unbounded.

            ``4`` : Other; see message for details.

        success : bool
            ``True`` when an optimal solution is found and ``False`` otherwise.

        message : str
            A string descriptor of the exit status of the algorithm.

        The following attributes will also be present, but the values may be
        ``None``, depending on the solution status.

        x : ndarray
            The values of the decision variables that minimize the
            objective function while satisfying the constraints.
        fun : float
            The optimal value of the objective function ``c @ x``.
        mip_node_count : int
            The number of subproblems or "nodes" solved by the MILP solver.
        mip_dual_bound : float
            The MILP solver's final estimate of the lower bound on the optimal
            solution.
        mip_gap : float
            The difference between the primal objective value and the dual
            objective bound, scaled by the primal objective value.

    Notes
    -----
    `milp` is a wrapper of the HiGHS linear optimization software [1]_. The
    algorithm is deterministic, and it typically finds the global optimum of
    moderately challenging mixed-integer linear programs (when it exists).

    References
    ----------
    .. [1] Huangfu, Q., Galabova, I., Feldmeier, M., and Hall, J. A. J.
           "HiGHS - high performance software for linear optimization."
           https://highs.dev/
    .. [2] Huangfu, Q. and Hall, J. A. J. "Parallelizing the dual revised
           simplex method." Mathematical Programming Computation, 10 (1),
           119-142, 2018. DOI: 10.1007/s12532-017-0130-5

    Examples
    --------
    Consider the problem at
    https://en.wikipedia.org/wiki/Integer_programming#Example, which is
    expressed as a maximization problem of two variables. Since `milp` requires
    that the problem be expressed as a minimization problem, the objective
    function coefficients on the decision variables are:

    >>> import numpy as np
    >>> c = -np.array([0, 1])

    Note the negative sign: we maximize the original objective function
    by minimizing the negative of the objective function.

    We collect the coefficients of the constraints into arrays like:

    >>> A = np.array([[-1, 1], [3, 2], [2, 3]])
    >>> b_u = np.array([1, 12, 12])
    >>> b_l = np.full_like(b_u, -np.inf, dtype=float)

    Because there is no lower limit on these constraints, we have defined a
    variable ``b_l`` full of values representing negative infinity. This may
    be unfamiliar to users of `scipy.optimize.linprog`, which only accepts
    "less than" (or "upper bound") inequality constraints of the form
    ``A_ub @ x <= b_u``. By accepting both ``b_l`` and ``b_u`` of constraints
    ``b_l <= A_ub @ x <= b_u``, `milp` makes it easy to specify "greater than"
    inequality constraints, "less than" inequality constraints, and equality
    constraints concisely.

    These arrays are collected into a single `LinearConstraint` object like:

    >>> from scipy.optimize import LinearConstraint
    >>> constraints = LinearConstraint(A, b_l, b_u)

    The non-negativity bounds on the decision variables are enforced by
    default, so we do not need to provide an argument for `bounds`.

    Finally, the problem states that both decision variables must be integers:

    >>> integrality = np.ones_like(c)

    We solve the problem like:

    >>> from scipy.optimize import milp
    >>> res = milp(c=c, constraints=constraints, integrality=integrality)
    >>> res.x
    [2.0, 2.0]

    Note that had we solved the relaxed problem (without integrality
    constraints):

    >>> res = milp(c=c, constraints=constraints)  # OR:
    >>> # from scipy.optimize import linprog; res = linprog(c, A, b_u)
    >>> res.x
    [1.8, 2.8]

    we would not have obtained the correct solution by rounding to the nearest
    integers.

    Other examples are given :ref:`in the tutorial <tutorial-optimize_milp>`.

    """
    args_iv = _milp_iv(c, integrality, bounds, constraints, options)
    c, integrality, lb, ub, indptr, indices, data, b_l, b_u, options = args_iv

    highs_res = _highs_wrapper(c, indptr, indices, data, b_l, b_u,
                               lb, ub, integrality, options)

    res = {}

    # Convert to scipy-style status and message
    highs_status = highs_res.get('status', None)
    highs_message = highs_res.get('message', None)
    status, message = _highs_to_scipy_status_message(highs_status,
                                                     highs_message)
    res['status'] = status
    res['message'] = message
    res['success'] = (status == 0)
    x = highs_res.get('x', None)
    res['x'] = np.array(x) if x is not None else None
    res['fun'] = highs_res.get('fun', None)
    res['mip_node_count'] = highs_res.get('mip_node_count', None)
    res['mip_dual_bound'] = highs_res.get('mip_dual_bound', None)
    res['mip_gap'] = highs_res.get('mip_gap', None)

    return OptimizeResult(res)

File: /usr/local/lib/python3.12/site-packages/scipy/optimize/_milp.py

Prompt: 79

Can you give me code to fill this in for the first example ('[.##.] (3) (1,3) (2) (2,3) (0,2) (0,1) {3,5,4,7}')

Assistant: 381

Sure! Here's the setup for the first example:

Copied!
from scipy.optimize import milp, LinearConstraint
import numpy as np

# First example
target = jolts[0]  # [3, 5, 4, 7]
buttons = btns[0]  # [[3], [1,3], [2], [2,3], [0,2], [0,1]]

# Objective: minimize total button presses (sum of all variables)
c = np.ones(len(buttons))

# Constraint matrix: each row is a counter, each column is a button
A = np.zeros((len(target), len(buttons)))
for j, btn in enumerate(buttons):
    for i in btn:
        A[i, j] = 1

# We want A @ x == target
constraints = LinearConstraint(A, target, target)

# All variables must be non-negative integers
integrality = np.ones(len(buttons))

res = milp(c=c, constraints=constraints, integrality=integrality)
print(f"Minimum presses: {res.fun}")
print(f"Button presses: {res.x}")

Try running this and see if you get 10 presses for the first example!

Code: 144 ()

lines = samp.splitlines()
btns = [re.findall(r'\([^)]+\)', l) for l in lines]
btns = [[list(map(int, b[1:-1].split(','))) for b in line] for line in btns]
jolts = [l.split("{")[1].split("}")[0] for l in lines]
jolts = [[int(x) for x in j.split(',')] for j in jolts]

Code: 334 ()

from scipy.optimize import milp, LinearConstraint
import numpy as np

# First example
target = jolts[0]  # [3, 5, 4, 7]
buttons = btns[0]  # [[3], [1,3], [2], [2,3], [0,2], [0,1]]

# Objective: minimize total button presses (sum of all variables)
c = np.ones(len(buttons))

# Constraint matrix: each row is a counter, each column is a button
A = np.zeros((len(target), len(buttons)))
for j, btn in enumerate(buttons):
    for i in btn:
        A[i, j] = 1

# We want A @ x == target
constraints = LinearConstraint(A, target, target)

# All variables must be non-negative integers
integrality = np.ones(len(buttons))

res = milp(c=c, constraints=constraints, integrality=integrality)
print(f"Minimum presses: {res.fun}")
print(f"Button presses: {res.x}")

Output: 58

Minimum presses: 10.0
Button presses: [1. 2. 0. 4. 0. 3.]

Prompt: 30

OK wrap this up in a solveb(samp) function so we can run on samp and inp

Assistant: 373

Copied!
def solveb(data):
    lines = data.splitlines()
    btns = [re.findall(r'\([^)]+\)', l) for l in lines]
    btns = [[list(map(int, b[1:-1].split(','))) for b in line] for line in btns]
    jolts = [l.split("{")[1].split("}")[0] for l in lines]
    jolts = [[int(x) for x in j.split(',')] for j in jolts]
    
    total = 0
    for target, buttons in zip(jolts, btns):
        c = np.ones(len(buttons))
        A = np.zeros((len(target), len(buttons)))
        for j, btn in enumerate(buttons):
            for i in btn:
                A[i, j] = 1
        constraints = LinearConstraint(A, target, target)
        integrality = np.ones(len(buttons))
        res = milp(c=c, constraints=constraints, integrality=integrality)
        total += res.fun
    return int(total)

Try solveb(samp) to verify it gives 33, then run on inp!

Code: 334 ()

def solveb(data):
    lines = data.splitlines()
    btns = [re.findall(r'\([^)]+\)', l) for l in lines]
    btns = [[list(map(int, b[1:-1].split(','))) for b in line] for line in btns]
    jolts = [l.split("{")[1].split("}")[0] for l in lines]
    jolts = [[int(x) for x in j.split(',')] for j in jolts]
    
    total = 0
    for target, buttons in zip(jolts, btns):
        c = np.ones(len(buttons))
        A = np.zeros((len(target), len(buttons)))
        for j, btn in enumerate(buttons):
            for i in btn:
                A[i, j] = 1
        constraints = LinearConstraint(A, target, target)
        integrality = np.ones(len(buttons))
        res = milp(c=c, constraints=constraints, integrality=integrality)
        total += res.fun
    return int(total)

Code: 7 ()

solveb(samp)

Output: 16

33

Code: 6 ()

solveb(inp)

Output: 18

18559