Github interview

## EASY:
```
def trap(height)
    drops = 0
    
    height.each_with_index do |current_height, i|
        max_occupancy = [height[0..i].max, height[i..-1].max].min
        drops += max_occupancy - current_height
    end
    
    drops
end
```

## HARD:
```
{
  original: -> land {
    left_max = 0
    right_max = 0
    left = 0
    right = land.length - 1
    volume = 0

    while left < right
      if land[left] > left_max
        left_max = land[left]
      end

      if land[right] > right_max
        right_max = land[right]
      end

      if left_max >= right_max
        volume += right_max - land[right]
        right -= 1
      else
        volume += left_max - land[left]
        left += 1
      end
    end

    volume
  },
```