modified day 4 and .gitignore

2021/day04a.py

@@ -0,0 +1,44 @@
+class Bingo:
+    def __init__(self, board):
+        self.board = [[int(n) for n in row.split()] for row in board.split("\n")]
+        self.skip = False
+
+    def winner(self):
+        for row in self.board:
+            if all(n == -1 for n in row):
+                self.skip = True
+                return True
+        for i in range(5):
+            column = [self.board[j][i] for j in range(5)]
+            if all(n == -1 for n in column):
+                self.skip = True
+                return True
+        return False
+
+    def draw(self, n):
+        for r, row in enumerate(self.board):
+            for c, num in enumerate(row):
+                if num == n:
+                    self.board[r][c] = -1
+
+    def unmarked_sum(self):
+        ans = 0
+        for row in self.board:
+            ans += sum(x for x in row if x != -1)
+        return ans
+
+
+f = open('input04.txt')
+numbers = map(int, next(f).strip().split(','))
+next(f)
+boards = [Bingo(b) for b in f.read().strip().split("\n\n")]
+
+def main():
+    for n in numbers:
+        for b in boards:
+            b.draw(n)
+            if b.winner():
+                return b.unmarked_sum() * n
+
+if __name__ == '__main__':
+    print(main())

2021/day04b.py

@@ -0,0 +1,17 @@
+from day04a import numbers, boards
+
+def main():
+    last_score = 0
+    for n in numbers:
+        for b in boards:
+            # skip if the Bingo board already won
+            if b.skip:
+                continue
+            b.draw(n)
+            if b.winner():
+                last_score = n * b.unmarked_sum()
+                print(last_score)
+    return last_score
+
+if __name__ == '__main__':
+    print(main())