Solve 2023:06 "Wait for it"

2023-python/output/day_06.py

@@ -0,0 +1,51 @@
+from math import prod, sqrt, ceil, floor
+from output import answer, puzzleinput
+
+n = 6
+title = "Wait For It"
+
+
+@answer(1, "The product of all record times for all races is {}")
+def part_1(presolved):
+    return presolved[0]
+
+
+@answer(2, "The product of all record times for the single long race is {}")
+def part_2(presolved):
+    return presolved[1]
+
+
+@puzzleinput(n)
+def parse_input(data):
+    return data
+
+
+def presolve(data):
+    values = data.split()
+    l = len(values) // 2
+    races = list(
+        map(
+            lambda x: (int(x[0]), int(x[1])), list(zip(values[: l + 1], values[l:]))[1:]
+        )
+    )
+    p1 = prod(sum(bpt * (t - bpt) > d for bpt in range(t)) for t, d in races)
+    t = int("".join(values[1:l]))
+    d = int("".join(values[l + 1 :]))
+    # quadratic formula:
+    # https://en.wikipedia.org/wiki/Quadratic_formula
+    l = ceil((-t + sqrt(t**2 - 4 * d)) / -2)
+    h = floor((-t - sqrt(t**2 - 4 * d)) / -2)
+    p2 = h - l + 1
+    return p1, p2
+
+
+if __name__ == "__main__":
+    inp = parse_input()
+
+    inp = presolve(inp)
+
+    a = part_1(inp)
+    b = part_2(inp)
+
+    assert a == 1083852
+    assert b == 23501589