Commit ac4cbff

@@ -0,0 +1,27 @@
+def assert(x, y)
+  raise [x, y].inspect unless x == y
+end
+
+class Solution
+  def self.run(buildings)
+    changes = []
+    result = []
+    buildings.each do |building|
+      left, right, height = building
+      left.upto(right) do |n|
+        changes[n] = height
+      end
+    end
+    current = nil
+    changes.each_with_index do |item, index|
+      next if item == current
+
+      current = item
+      result << [index, item]
+    end
+    result << [changes.size, 0]
+    result
+  end
+end
+
+assert Solution.run([[2,8,3], [4,6,5]]), [[2,3], [4,5], [7,3], [9,0]]