day 13, solve linear equations

d13/part1.py

@@ -0,0 +1,19 @@
+import sys
+from aoc import nums
+
+MOVES = sorted([(i,j)
+    for i in range(1,101)
+        for j in range(1,101)
+], key=lambda x:3*x[0]+x[1])
+
+S = 0
+for i in sys.stdin.read().strip().split('\n\n'):
+    [a,b,p] = i.split("\n")
+    (xa, ya) = nums(a)
+    (xb, yb) = nums(b)
+    (xp, yp) = nums(p)
+    for (i,j) in MOVES:
+        if xa*i+xb*j==xp and ya*i+yb*j==yp:
+            S += 3*i+j
+            break
+print(S)

d13/part2.py

@@ -0,0 +1,31 @@
+import sys
+from aoc import nums
+import sympy as sym
+from sympy.core.numbers import Integer
+
+x,y = sym.symbols('x,y')
+
+def solve(a,b,p, part2=False):
+    (xa, ya) = a
+    (xb, yb) = b
+    (xp, yp) = p
+    T = 10_000_000_000_000 if part2 else 0
+    eq1 = sym.Eq(x*xa+y*xb, xp+T)
+    eq2 = sym.Eq(x*ya+y*yb, yp+T)
+    result = sym.solve([eq1,eq2],(x,y))
+    if type(result[x]) is not Integer or type(result[y]) is not Integer:
+        return 0
+    elif not part2 and (result[x]>100 or result[y]>100):
+        return 0
+    else:
+        return result[x]*3 + result[y]
+
+S1 = S2 = 0
+for i in sys.stdin.read().strip().split('\n\n'):
+    [a,b,p] = i.split("\n")
+    a = nums(a)
+    b = nums(b)
+    p = nums(p)
+    S1 += solve(a,b,p)
+    S2 += solve(a,b,p,part2=True)
+print(S1, S2)

lib/aoc.py

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+import re
+
+def nums(s:str) -> list[int]:
+    return list(map(int,re.findall(r'-?\d+',s)))
+
+
+TESTS = [
+    ("", []),
+    ("9738: 7 89 52 75 8 1", [9738, 7, 89, 52, 75, 8, 1]),
+    ("p=62,20 v=85,-14", [62, 20, 85, -14]),
+    ("24 25 28 31 28", [24, 25, 28, 31, 28]),
+    ("how():mul(422,702)'how()'", [422,702]),
+    ("58692       56129", [58692, 56129]),
+    ("Button A: X+16, Y+32", [16, 32]),
+    ("46,51,67,25,72,77,13,96,36,76,52,23", [46,51,67,25,72,77,13,96,36,76,52,23]),
+    ("47|53", [47,53]),
+    ("..........M..........j.............y.....O........", []),
+]
+
+if __name__ == "__main__":
+    for (q,a) in TESTS:
+        assert nums(q) == a
+    a, b = nums("how():mul(422,702)'how()'")
+    assert a == 422
+    assert b == 702