a-z代表不同顏色的氣球，相鄰氣球顏色相同的話每次可以保留其中一個，花費時間為二者needTime中間的較小值，問消除全部的相鄰氣球的最小總花費，貪心
#1578
#Runtime: 812 ms (Beats 62.22%)
#Memory: 22.1 MB (Beats 88.89%)
class Solution(object):
def minCost(self, colors, neededTime):
"""
:type colors: str
:type neededTime: List[int]
:rtype: int
"""
ans = 0
for i in xrange(1, len(neededTime)):
if colors[i] == colors[i - 1]:
ans += min(neededTime[i], neededTime[i - 1])
neededTime[i] = max(neededTime[i - 1], neededTime[i])
return ans