Added solutions for day 9

askrepps · askrepps · commit 891bae881bac · 2020-12-09T20:42:26.000-05:00
diff --git a/advent2020/day9.py b/advent2020/day9.py
@@ -0,0 +1,59 @@
+# MIT License
+#
+# Copyright (c) 2020 Andrew Krepps
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+from . import day1
+from . import util
+
+
+def find_invalid_number(numbers, preamble_length):
+    for idx in range(preamble_length, len(numbers)):
+        num = numbers[idx]
+        if day1.find_sum_pair(numbers[idx - preamble_length:idx], num) is None:
+            return num
+    return None
+
+
+def find_contiguous_sum(numbers, target):
+    for length in range(2, len(numbers)):
+        for idx in range(len(numbers) - length + 1):
+            contiguous_range = numbers[idx:idx+length]
+            if sum(numbers[idx:idx+length]) == target:
+                return contiguous_range
+    return None
+
+
+def get_part1_answer(numbers):
+    return find_invalid_number(numbers, 25)
+
+
+def get_part2_answer(numbers, invalid_num):
+    contiguous_range = find_contiguous_sum(numbers, invalid_num)
+    return min(contiguous_range) + max(contiguous_range)
+
+
+def run():
+    with open(util.get_input_file_path("day9.txt")) as f:
+        numbers = [int(line) for line in f if len(line.strip()) > 0]
+        invalid_num = get_part1_answer(numbers)
+        print(f"The answer to part 1 is {invalid_num}")
+        print(f"The answer to part 2 is {get_part2_answer(numbers, invalid_num)}")
diff --git a/main.py b/main.py
@@ -31,6 +31,7 @@
 from advent2020 import day6
 from advent2020 import day7
 from advent2020 import day8
+from advent2020 import day9
 
 
 day_runners = [
@@ -41,7 +42,8 @@
     lambda: day5.run(),
     lambda: day6.run(),
     lambda: day7.run(),
-    lambda: day8.run()
+    lambda: day8.run(),
+    lambda: day9.run()
 ]
 
 
diff --git a/test/test_day9.py b/test/test_day9.py
@@ -0,0 +1,58 @@
+# MIT License
+#
+# Copyright (c) 2020 Andrew Krepps
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+
+import unittest
+
+from advent2020.day9 import find_contiguous_sum
+from advent2020.day9 import find_invalid_number
+
+
+data = """
+35
+20
+15
+25
+47
+40
+62
+55
+65
+95
+102
+117
+150
+182
+127
+219
+299
+277
+309
+576
+"""
+
+
+class Day9Test(unittest.TestCase):
+    def test_day9_part1(self):
+        numbers = [int(line) for line in data.split("\n") if len(line.strip()) > 0]
+        self.assertEqual(find_invalid_number(numbers, 5), 127)
+        self.assertListEqual(find_contiguous_sum(numbers, 127), [15, 25, 47, 40])
