```
class Solution:
# @param {integer[]} ratings
# @return {integer}
def candy(self, ratings):
# use two pass scan from left to right and vice versa to keep the candy level up to now
# similar to like the Trapping Rain Water question
res = [1]*len(ratings) # also compatable with [] input
lbase = rbase = 1
# left scan
for i in xrange(1, len(ratings)):
lbase = lbase + 1 if ratings[i] > ratings[i-1] else 1
res[i] = lbase
# right scan
for i in xrange(len(ratings)-2, -1, -1):
rbase = rbase + 1 if ratings[i] > ratings[i+1] else 1
res[i] = max(rbase, res[i])
return sum(res)
```