Add day 6 solutions

python/2023/src/andy_aoc_2023/day6.py

@@ -0,0 +1,90 @@
+from collections import defaultdict
+from functools import reduce
+import math
+from pprint import pprint
+import re
+import sys
+
+
+def parse_raw_input(lines):
+    return [
+        re.split(
+            r"\s+",
+            re.split(r":\s+", line)[1].strip()
+        )
+        for line in lines
+    ]
+
+def distance_traveled(pressed, total_time):
+    return pressed * (total_time - pressed)
+
+def part1(lines):
+
+    data = []
+    for line in lines:
+        data.append([int(num) for num in line])
+
+    races = list(
+        map(lambda *args: list(args),
+            *data)
+    )
+
+    outputs = defaultdict(lambda : 0)
+    for i, (total_time, record) in enumerate(races):
+        for pressed in range(total_time + 1):
+            d = distance_traveled(pressed, total_time)
+            if d > record:
+                outputs[i] += 1
+
+    pprint(dict(outputs))
+    print(reduce(lambda x,y: x*y, outputs.values(), 1))
+
+
+def distance_between_roots(b, c):
+    """Because we pass in non-zero `c`, this isn't a root, just the intersection"""
+    # y = -x**2 + bx + 0
+    # a = -1 , b = b, c = -c
+
+    # x = -b +- sqrt(b**2 - 4ac) / 2a
+    root = math.sqrt( b**2 - (4 * c) )
+    x1 = (-b + root) / (-2)
+    x2 = (-b - root) / (-2)
+    print(f"  root {root}, x1 {x1}, x2 {x2}")
+    return int(x2) - int(x1)
+
+def part2(input):
+    total_time, record = [int("".join(line)) for line in input]
+
+    # x = -b +- sqrt(b**2 - 4ac) / 2a
+    root = math.sqrt( total_time**2 - (4 * record) )
+    x1 = (-total_time + root) // (-2)
+    x2 = (-total_time - root) // (-2)
+    print(f"  root {root}, x1 {x1}, x2 {x2}")
+    print(int(x2) - int(x1))
+
+
+with open(sys.argv[1]) as infile:
+    input = parse_raw_input(infile.readlines())
+
+part1(input)
+part2(input)
+
+print("--- EXPERIMENTAL ---")
+
+data = []
+for line in input:
+    data.append([int(num) for num in line])
+
+races = list(
+    map(lambda *args: list(args),
+        *data)
+)
+
+outputs = {}
+for i, (total_time, record) in enumerate(races):
+    print(f"time {total_time}, record {record}")
+    outputs[i] = distance_between_roots(total_time, record)
+
+pprint(outputs)
+
+print(reduce(lambda x,y: x*y, outputs.values(), 1))