day05 solution

.gitignore

@@ -1,2 +1,2 @@
-data.txt
+*.txt
 *.pyc

day05/solve.py

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+# Day 05: Supply Stacks
+
+import os
+import re
+
+# The moves part of the input data have been put into a separate file
+def get_moves_path():
+  return os.path.join(os.path.dirname(__file__), 'moves.txt')
+
+# The stacks part of the input data have been transformed into rows instead of columns and put into a separate file
+# Each row represents a stack with the bottom crate starting in the first index. letter are separated by spaces
+def get_stacks_path():
+  return os.path.join(os.path.dirname(__file__), 'stacks.txt')
+
+def get_last(arr):
+  return arr[-1]
+
+def solve_part1():
+  stacks = map(str.split, open(get_stacks_path()).readlines())
+  # print(stacks)
+
+  with open(get_moves_path()) as moves:
+    for move in moves:
+      [count, source, dest] = map(int, re.match('move (\d+) from (\d+) to (\d+)', move).groups())
+      for _ in range(count):
+        stacks[dest - 1].append(stacks[source - 1].pop())
+      # print('Moved %d from stack %d to stack %d' % (count, source, dest))
+
+  print('GOAL: Which crate will end up on top of each stack?')
+  print('ANSWER: After the rearrangement procedure completes, what crate ends up on top of each stack?')
+  tops = ''.join(map(get_last, stacks))
+  print('Tops: %s' % (tops))
+
+def solve_part2():
+  stacks = map(str.split, open(get_stacks_path()).readlines())
+  # print(stacks)
+
+  with open(get_moves_path()) as moves:
+    for move in moves:
+      [count, source, dest] = map(int, re.match('move (\d+) from (\d+) to (\d+)', move).groups())
+      # print('moving %d items from %s to %s' % (count, stacks[source-1], stacks[dest-1]))
+      moved_items = stacks[source-1][-count:]
+      del stacks[source-1][-count:]
+      stacks[dest-1] += moved_items
+  
+  print('ANSWER: After the rearrangement procedure completes, what crate ends up on top of each stack?')
+  tops = ''.join(map(get_last, stacks))
+  print('Tops: %s' % (tops))
+
+if __name__ == '__main__':
+  solve_part1()
+  solve_part2()

day05/tests.py

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+import unittest
+
+class Day05TestMethods(unittest.TestCase):
+  def setUp(self):
+    pass
+
+  # Does a thing
+  def test_true(self):
+    self.assertEqual(True, False)
+  
+if __name__ == '__main__':
+  unittest.main()