day 4 part 1 solution (#7)

Co-authored-by: James <james@Susans-MacBook-Air.local>

Author: jameslawlor

Makefile

@@ -13,4 +13,5 @@ solutions:
 	python3 src/aoc_2023/days/1.py --input_file inputs/1.txt --part 1
 	python3 src/aoc_2023/days/1.py --input_file inputs/1.txt --part 2
 	python3 src/aoc_2023/days/2.py --input_file inputs/2.txt
-	python3 src/aoc_2023/days/3.py --input_file inputs/3.txt
+	python3 src/aoc_2023/days/3.py --input_file inputs/3.txt
+	python3 src/aoc_2023/days/4.py --input_file inputs/4.txt

README.md

@@ -14,4 +14,4 @@ docker run aoc-2023-app
 | 01 | ⭐️ | ⭐️ |
 | 02 | ⭐️ | ⭐️ |
 | 03 | ⭐️ | ⭐️ |
-| 04 | todo | todo |
+| 04 | ⭐️ | todo |

src/aoc_2023/days/4.py

@@ -0,0 +1,15 @@
+from aoc_2023.solvers.day_4_solvers import (
+    solve_day_4,
+)
+from aoc_2023.utils.input_handling import read_input, parse_args
+
+
+def main():
+    args = parse_args()
+    input = read_input(args.input_file)
+    result_part_1 = solve_day_4(input)
+    print(f"Day 4. Total points for part 1 is {result_part_1}. ")
+
+
+if __name__ == "__main__":
+    main()

src/aoc_2023/solvers/day_4_solvers.py

@@ -0,0 +1,62 @@
+import re
+
+
+class Card:
+    def __init__(self, card_number, winning_numbers, numbers_i_have):
+        self.card_number = card_number
+        self.winning_numbers = winning_numbers
+        self.numbers_i_have = numbers_i_have
+        self.n_winners = None
+        self.points = None
+
+    def __str__(self):
+        return (
+            f"Card {self.card_number}: {self.winning_numbers} | "
+            f"{self.numbers_i_have} | "
+            f"n_winners: {self.n_winners} | points: {self.points}"
+        )
+
+    def find_n_winners(self):
+        self.n_winners = sum(
+            [1 for n in self.numbers_i_have if n in self.winning_numbers]
+        )
+
+    def compute_points(self):
+        if self.n_winners > 0:
+            self.points = 2 ** (self.n_winners - 1)
+        else:
+            self.points = 0
+
+
+def parse_input_line(line):
+    card_number = re.findall(r"(\d+)", line.split(":")[0])[0]
+    all_numbers = line.split(":")[1]
+    [winning_numbers, numbers_i_have] = all_numbers.split("|")
+    winning_numbers = re.findall(r"(\d+)", winning_numbers)
+    numbers_i_have = re.findall(r"(\d+)", numbers_i_have)
+
+    return (card_number, winning_numbers, numbers_i_have)
+
+
+def create_cards(input_txt):
+    cards = []
+    for line in input_txt:
+        (card_number, winning_numbers, numbers_i_have) = parse_input_line(line)
+        card = Card(card_number, winning_numbers, numbers_i_have)
+        cards.append(card)
+    return cards
+
+
+def compute_total_score(cards):
+    total_score = 0
+    for card in cards:
+        card.find_n_winners()
+        card.compute_points()
+        total_score += card.points
+    return total_score
+
+
+def solve_day_4(input) -> int:
+    cards = create_cards(input)
+    total_score = compute_total_score(cards)
+    return total_score

tests/test_day_4_solvers.py

@@ -0,0 +1,30 @@
+import pytest
+from aoc_2023.solvers.day_4_solvers import solve_day_4
+
+
+@pytest.fixture
+def day_4_test_input():
+    return [
+        "Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53",
+        "Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19",
+        "Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1",
+        "Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83",
+        "Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36",
+        "Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11",
+    ]
+
+
+@pytest.fixture
+def day_4_expected_scores():
+    return [
+        8,
+        2,
+        2,
+        1,
+        0,
+        0,
+    ]
+
+
+def test_solve_day_4(day_4_test_input, day_4_expected_scores):
+    assert solve_day_4(day_4_test_input) == sum(day_4_expected_scores)