1 files changed, 56 insertions, 0 deletions
diff --git a/day08/part1.rb b/day08/part1.rb
new file mode 100644
index 0000000..7bd78ad
--- /dev/null
+++ b/day08/part1.rb
@@ -0,0 +1,56 @@
+def check_up(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ri -= 1
+    break if ri < 0
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+def check_down(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ri += 1
+    break if ri >= grid.count
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+def check_left(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ci -= 1
+    break if ci < 0
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+def check_right(grid, ri, ci)
+  tree = grid[ri][ci]
+  loop do
+    ci += 1
+    break if ci >= grid[ri].count
+    return false unless grid[ri][ci] < tree
+  end
+  true
+end
+
+grid = $stdin.readlines.map(&:strip).map(&:chars).map { |row| row.map(&:to_i) }
+
+num_visible = 0
+
+grid.count.times do |ri|
+  grid[ri].count.times do |ci|
+    visible = false
+    visible = true if check_up(grid, ri, ci)
+    visible = true if check_down(grid, ri, ci)
+    visible = true if check_left(grid, ri, ci)
+    visible = true if check_right(grid, ri, ci)
+    num_visible += 1 if visible
+  end
+end
+
+puts num_visible