day08 solution

day08/solve.py

@@ -0,0 +1,91 @@
+# Day 08: Treetop Tree House
+
+import os
+
+def get_path():
+  return os.path.join(os.path.dirname(__file__), 'data.txt')
+
+def build_grid():
+  grid = []
+  with open(get_path()) as fp:
+    for line in fp:
+      grid.append(map(int, line.strip()))
+  return grid
+
+def get_column(grid, col_idx):
+  return map(lambda row: row[col_idx], grid)
+
+def is_visible(grid, row_idx, col_idx):
+  # all edge trees are visible
+  if row_idx == 0 or row_idx == len(grid) -1 \
+    or col_idx == 0 or col_idx == len(grid[0]) - 1:
+    return True
+  cell = grid[row_idx][col_idx]
+  # check the left side
+  if all([item < cell for item in grid[row_idx][:col_idx]]):
+    return True
+  # check the right side
+  if all([item < cell for item in grid[row_idx][col_idx+1:]]):
+    return True
+  # check the top
+  if all([item < cell for item in get_column(grid, col_idx)[:row_idx]]):
+    return True
+  # check the bottom
+  if all([item < cell for item in get_column(grid, col_idx)[row_idx+1:]]):
+    return True
+  return False
+
+def score_row(height, row):
+  score = 0
+  for item in row:
+    score += 1
+    if item >= height:
+      break
+  return score
+
+def get_score(grid, row_idx, col_idx):
+  # all edge trees will have at least one size with a 0 score
+  if row_idx == 0 or row_idx == len(grid) -1 \
+    or col_idx == 0 or col_idx == len(grid[0]) - 1:
+    return 0
+
+  height = grid[row_idx][col_idx]
+  left_score = score_row(height, grid[row_idx][:col_idx][::-1]) # [::-1] reverses a slice. who knew? 
+  right_score = score_row(height, grid[row_idx][col_idx+1:])
+  top_score = score_row(height, get_column(grid, col_idx)[:row_idx][::-1]) # reverse it because we are looking "backwards"
+  bottom_score = score_row(height, get_column(grid, col_idx)[row_idx+1:])
+  total_score = left_score * right_score * top_score * bottom_score
+  # print ('grid[%d][%d] = %d, (%d, %d, %d, %d) = %d' % (row_idx, col_idx, height, left_score, right_score, top_score, bottom_score, total_score))
+  return total_score
+
+def solve_part1():
+  total = 0
+
+  grid = build_grid()
+  # print('height %d, width %d' % (len(grid), len(grid[0])))
+  for row_idx in range(0, len(grid)):
+    for col_idx in range(0, len(grid[row_idx])):
+      if is_visible(grid, row_idx, col_idx):
+        total += 1
+
+  print('Day 08: Part 1')
+  print('GOAL: Count the number of trees that are visible from outside the grid when looking directly along a row or column.')
+  print('ANSWER: How many trees are visible from outside the grid?')
+  print('Total: %d' % (total))
+
+def solve_part2():
+  best_score = 0
+  grid = build_grid()
+  for row_idx in range(0, len(grid)):
+    for col_idx in range(0, len(grid[row_idx])):
+      score = get_score(grid, row_idx, col_idx)
+      best_score = score if score > best_score else best_score
+
+  print('Day 08: Part 2')  
+  print('GOAL: Consider each tree on your map.')
+  print('ANSWER: What is the highest scenic score possible for any tree?')
+  print('Best Score: %d' % (best_score))
+
+if __name__ == '__main__':
+  solve_part1()
+  solve_part2()

day08/tests.py

@@ -0,0 +1,20 @@
+import unittest
+import solve
+
+class Day08TestMethods(unittest.TestCase):
+  def setUp(self):
+    pass
+
+  def test_score_row(self):
+    test_cases = [
+      [1, 5, [3]],
+      [1, 5, [5,2]],
+      [2, 5, [1,2]],
+      [2, 5, [3,5,3]],
+      [2, 5, [3,3]]
+    ]
+    for [expected, height, row] in test_cases:
+      self.assertEqual(solve.score_row(height, row), expected)
+  
+if __name__ == '__main__':
+  unittest.main()

tests.py.template

@@ -1,4 +1,5 @@
 import unittest
+import solve
 
 class Day#DAY#TestMethods(unittest.TestCase):
   def setUp(self):
@@ -6,7 +7,11 @@ class Day#DAY#TestMethods(unittest.TestCase):
 
   # Does a thing
   def test_true(self):
-    self.assertEqual(True, False)
+      test_cases = [
+        [True, False]
+    ]
+    for [expected, value] in test_cases:
+    self.assertEqual(expected, value)
   
 if __name__ == '__main__':
   unittest.main()