This is in response to another [gist](https://gist.github.com/igor47/7228586) for a supposed solution to the [water levels question](https://news.ycombinator.com/item?id=6639839). The solution doesn't work if there is more than 1 "puddle". Example: `[2,5,1,2,3,4,7,7,6,3,5]` should return 12.

gistfile1.py

#!/usr/bin/python
 
def water(levels):
   # state machine
   filling = False
   h = 0
   total = 0
   cur = 0
 
   for i in xrange(1, len(levels)):
      # we can start filling once we see a first drop in level
      if not filling and levels[i] < levels[i-1]:
         filling = True
         h = levels[i-1]
 
      if filling:
         # we need to stop filling if level is above the original wall
         if levels[i] >= h:
            total += cur
            cur = 0
            filling = False
 
         # otherwise, count this level as a puddle
         else:
            cur += h - levels[i]
 
   return total
 
if __name__ == "__main__":
   testcases = [
         ([1,0,1], 1),
         ([5,0,5], 5),
         ([0,1,0,1,0], 1),
         ([1,0,1,0], 1),
         ([1,0,1,2,0,2], 3),
         ([2,5,1,2,3,4,7,7,6], 10),
         ([2,5,1,2,3,4,7,7,6,3,5], 12), # fails
         ]
 
   for case in testcases:
      w = water(case[0])
      if w == case[1]:
         print "TRUE: %s holds %s" % (case[0], w)
      else:
         print "MISMATCH: %s holds %s (got %s)" % (case[0], case[1], w)