Add solution to 2025-12-10

Author: fuglede

2025/day10/solutions.py

@@ -0,0 +1,47 @@
+import numpy as np
+from scipy.optimize import linprog
+from collections import deque
+
+
+with open("input") as f:
+    ls = f.read().strip().split("\n")
+
+tasks = []
+for l in ls:
+    toggles, *buttons, counters = l.split()
+    toggles = set(i for i, x in enumerate(toggles[1:-1]) if x == "#")
+    moves = [set(map(int, b[1:-1].split(","))) for b in buttons]
+    counters = tuple(map(int, counters[1:-1].split(",")))
+    tasks.append((toggles, moves, counters))
+
+
+def solve1(goal, moves):
+    q = deque()
+    q.append((set(), 0))
+    seen = set()
+    while q:
+        curr, steps = q.popleft()
+        if curr == goal:
+            return steps
+        for m in moves:
+            newset = curr ^ m
+            if newset in seen:
+                continue
+            seen.add(frozenset(newset))
+            q.append((newset, steps + 1))
+
+
+print(sum(solve1(goal, moves) for goal, moves, _ in tasks))
+
+
+# Part 2
+def solve2(goal, moves):
+    c = np.ones(len(moves))
+    A_eq = np.zeros((len(goal), len(moves)))
+    b_eq = np.array(goal)
+    for i in range(len(goal)):
+        A_eq[i] = [i in m for m in moves]
+    return linprog(c, A_eq=A_eq, b_eq=b_eq, integrality=True).fun
+
+
+print(sum(solve2(counters, moves) for _, moves, counters in tasks))