Hill Pooling Solution

gistfile1.txt

def hills(terrain)
    return 0 if terrain.empty?
    forward_pool_depths = find_pools(terrain, "forward")
    reverse_pool_depths = find_pools(terrain.reverse, "reverse")
    return (forward_pool_depths + reverse_pool_depths)
end

def find_pools(terrain, direction)
    highest_point = 0
    potential_pools = []
    total_depth = 0

    terrain.map do |height|
        if (height > highest_point)
            total_depth += pool_depths(potential_pools, highest_point)
            highest_point = height
            potential_pools = []
        elsif (height == highest_point && direction == "forward")
            total_depth += pool_depths(potential_pools, highest_point)
            highest_point = height
            potential_pools = []
        else
            potential_pools.push(height)
        end
    end
    return total_depth
end

def pool_depths(potential_pools, highest_point)
    return 0 if potential_pools.empty?
    potential_pools.compact.map { |n| highest_point - n }.sum
end