Solve 2021:7 "The Treachery of Whales"

2021-python/solutions/day_07.py

@@ -0,0 +1,36 @@
+from solutions import BaseSolution
+
+
+class Solution(BaseSolution):
+    input_file = "07.txt"
+
+    def __str__(self):
+        return "Day 7: The Treachery of Whales"
+
+    def parse_input(self, data):
+        return [int(d) for d in data.strip().split(",")]
+
+    def solve(self, puzzle_input):
+        return min(
+            [
+                sum(abs(start - pos) for start in puzzle_input)
+                for pos in range(max(puzzle_input))
+            ]
+        )
+
+    def solve_again(self, puzzle_input):
+        l = sum(range(max(puzzle_input))) * len(puzzle_input)
+        for pos in range(max(puzzle_input)):
+            l = min(
+                l,
+                sum(
+                    abs(start - pos) + sum(range(abs(start - pos)))
+                    for start in puzzle_input
+                ),
+            )
+        return l
+
+
+if __name__ == "__main__":
+    solution = Solution()
+    solution.show_results()

2021-python/tests/test_day_07.py

@@ -0,0 +1,29 @@
+import unittest
+
+from solutions.day_07 import Solution
+
+
+class Day07TestCase(unittest.TestCase):
+    def setUp(self):
+        self.solution = Solution()
+        self.puzzle_input = self.solution.parse_input(
+            """
+        16,1,2,0,4,2,7,1,2,14
+        """
+        )
+
+    def test_parse_puzzle_input(self):
+        data = """
+        16,1,2
+        """
+        assert self.solution.parse_input(data) == [16, 1, 2]
+
+    def test_solve_first_part(self):
+        assert self.solution.solve(self.puzzle_input) == 37
+
+    def test_solve_second_part(self):
+        assert self.solution.solve_again(self.puzzle_input) == 168
+
+
+if __name__ == "__main__":
+    unittest.main()