Twitter Interview Solution in Python (http://qandwhat.apps.runkite.com/i-failed-a-twitter-interview/ and https://gist.github.com/mkozakov/59af0fd5bddbed1a0399)

gistfile1.py

heights = [2, 5, 1, 2, 3, 4, 7, 7, 6]

totalWater = 0

for index in range(0, len(heights)):
	currentHeight = heights[index]
	maxLeftHeight = max(heights[:index]) if index > 0 else 0
	maxRightHeight = max(heights[index:])
	smallestMaxHeight = min(maxLeftHeight, maxRightHeight)
	water = smallestMaxHeight - currentHeight if smallestMaxHeight - currentHeight > 0 else 0
	print("{}{}".format("X" * currentHeight, "w" * water))
	totalWater = totalWater + water

print("Total Water: {}".format(totalWater))