d4p2 solution done (#8)

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

Author: jameslawlor

README.md

@@ -14,4 +14,5 @@ docker run aoc-2023-app
 | 01 | ⭐️ | ⭐️ |
 | 02 | ⭐️ | ⭐️ |
 | 03 | ⭐️ | ⭐️ |
-| 04 | ⭐️ | todo |
+| 04 | ⭐️ | ⭐️ |
+| 05 | todo | todo |

src/aoc_2023/days/4.py

@@ -7,8 +7,10 @@
 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}. ")
+    result_part_1, result_part_2 = solve_day_4(input)
+    print(f"Day 4: "
+          f" Total points for part 1 is {result_part_1}. "
+          f" Total points for part 2 is {result_part_2}. ")
 
 
 if __name__ == "__main__":

src/aoc_2023/solvers/day_4_solvers.py

@@ -6,24 +6,27 @@ 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.n_matches = None
         self.points = None
+        self.n_copies = 1
 
     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}"
+            f"n_matches: {self.n_matches} | "
+            f"points: {self.points} | "
+            f"n_copies: {self.n_copies}"
         )
 
-    def find_n_winners(self):
-        self.n_winners = sum(
+    def find_n_matches(self):
+        self.n_matches = 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)
+        if self.n_matches > 0:
+            self.points = 2 ** (self.n_matches - 1)
         else:
             self.points = 0
 
@@ -50,13 +53,25 @@ def create_cards(input_txt):
 def compute_total_score(cards):
     total_score = 0
     for card in cards:
-        card.find_n_winners()
+        card.find_n_matches()
         card.compute_points()
         total_score += card.points
     return total_score
 
 
+def compute_copies(cards):
+    for card_number, card in enumerate(cards):
+        n_matches_on_card = card.n_matches
+        n_copies_of_card = card.n_copies
+        copies_to_generate = n_copies_of_card
+        for next_card in cards[card_number+1 : card_number + n_matches_on_card + 1]:
+            next_card.n_copies += copies_to_generate
+    return cards
+
+
 def solve_day_4(input) -> int:
     cards = create_cards(input)
     total_score = compute_total_score(cards)
-    return total_score
+    cards_with_copies = compute_copies(cards)
+    n_scratchcards = sum([card.n_copies for card in cards_with_copies])
+    return (total_score, n_scratchcards)

tests/test_day_4_solvers.py

@@ -1,5 +1,10 @@
 import pytest
-from aoc_2023.solvers.day_4_solvers import solve_day_4
+from aoc_2023.solvers.day_4_solvers import (
+    solve_day_4,
+    compute_copies,
+    create_cards,
+    compute_total_score,
+)
 
 
 @pytest.fixture
@@ -26,5 +31,26 @@ def day_4_expected_scores():
     ]
 
 
-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)
+@pytest.fixture
+def day_4_expected_final_cards_count():
+    return [1, 2, 4, 8, 14, 1]
+
+
+def test_day_4_expected_final_cards_count(day_4_expected_final_cards_count):
+    assert sum(day_4_expected_final_cards_count) == 30
+
+
+def test_solve_day_4(
+    day_4_test_input, day_4_expected_scores, day_4_expected_final_cards_count
+):
+    assert solve_day_4(day_4_test_input) == (
+        sum(day_4_expected_scores),
+        sum(day_4_expected_final_cards_count),
+    )
+
+def test_compute_copies(day_4_test_input,day_4_expected_final_cards_count):
+    test_cards = create_cards(day_4_test_input)
+    compute_total_score(test_cards)
+    test_cards_with_copies = compute_copies(test_cards)
+    test_n_scratchcards = [card.n_copies for card in test_cards_with_copies]
+    assert test_n_scratchcards == day_4_expected_final_cards_count