Day 6: Wait For It

README.md

@@ -10,4 +10,4 @@ Development occurs in language-specific directories:
 |[Day3.hs](hs/src/Day3.hs)|[Day3.kt](kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day3.kt)|[day3.py](py/aoc2023/day3.py)|[day3.rs](rs/src/day3.rs)|
 |[Day4.hs](hs/src/Day4.hs)|[Day4.kt](kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day4.kt)|[day4.py](py/aoc2023/day4.py)|[day4.rs](rs/src/day4.rs)|
 |[Day5.hs](hs/src/Day5.hs)|[Day5.kt](kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day5.kt)|[day5.py](py/aoc2023/day5.py)|[day5.rs](rs/src/day5.rs)|
-|[Day6.hs](hs/src/Day6.hs)|[Day6.kt](kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day6.kt)|||
+|[Day6.hs](hs/src/Day6.hs)|[Day6.kt](kt/aoc2023-lib/src/commonMain/kotlin/com/github/ephemient/aoc2023/Day6.kt)|[day6.py](py/aoc2023/day6.py)||

py/aoc2023/day6.py

@@ -0,0 +1,45 @@
+"""
+Day 6: Wait For It
+"""
+
+import re
+from math import ceil, floor, prod, sqrt
+
+SAMPLE_INPUT = """
+Time:      7  15   30
+Distance:  9  40  200
+"""
+
+NUMBER = re.compile(r"\d+")
+
+
+def _wincount(time, distance):
+    b = time / 2
+    d = sqrt(b * b - distance)
+    return ceil(b + d - 1) - floor(b - d + 1) + 1
+
+
+def part1(data):
+    """
+    >>> part1(SAMPLE_INPUT)
+    288
+    """
+    line1, line2 = filter(None, data.splitlines())
+    return prod(
+        _wincount(int(time.group()), int(distance.group()))
+        for time, distance in zip(NUMBER.finditer(line1), NUMBER.finditer(line2))
+    )
+
+
+def part2(data):
+    """
+    >>> part2(SAMPLE_INPUT)
+    71503
+    """
+    line1, line2 = filter(None, data.splitlines())
+    return _wincount(
+        int("".join(NUMBER.findall(line1))), int("".join(NUMBER.findall(line2)))
+    )
+
+
+parts = (part1, part2)

py/pyproject.toml

@@ -27,6 +27,7 @@ day2 = "aoc2023.day2:parts"
 day3 = "aoc2023.day3:parts"
 day4 = "aoc2023.day4:parts"
 day5 = "aoc2023.day5:parts"
+day6 = "aoc2023.day6:parts"
 
 [tool.black]
 target_version = ["py312"]