Poetry stuff.

src/holt59/aoc/2023/day6.py

@@ -0,0 +1,47 @@
+import math
+import sys
+
+
+def extreme_times_to_beat(time: int, distance: int) -> tuple[int, int]:
+    # formula (T = total time, D = target distance)
+    # - speed(t) = t,
+    # - distance(t) = (T - t) * speed(t)
+    # - distance(t) > D
+    #   <=> (T - t) * t > D
+    #   <=> -t^2 + T * t - D >= 0
+
+    a, b, c = -1, time, -distance
+    d = b * b - 4 * a * c
+
+    t1 = math.ceil(-(b - math.sqrt(d)) / (2 * a))
+    t2 = math.floor(-(b + math.sqrt(d)) / (2 * a))
+
+    if (time - t1) * t1 == distance:
+        t1 += 1
+
+    if (time - t2) * t2 == distance:
+        t2 -= 1
+
+    return t1, t2
+
+
+lines = sys.stdin.read().splitlines()
+
+# part 1
+times = list(map(int, lines[0].split()[1:]))
+distances = list(map(int, lines[1].split()[1:]))
+answer_1 = math.prod(
+    t2 - t1 + 1
+    for t1, t2 in (
+        extreme_times_to_beat(time, distance)
+        for time, distance in zip(times, distances)
+    )
+)
+print(f"answer 1 is {answer_1}")
+
+# part 2
+time = int(lines[0].split(":")[1].strip().replace(" ", ""))
+distance = int(lines[1].split(":")[1].strip().replace(" ", ""))
+t1, t2 = extreme_times_to_beat(time, distance)
+answer_2 = t2 - t1 + 1
+print(f"answer 2 is {answer_2}")