The solution is guaranteed to be unique.
首先判断总的油够不够consume,如果总的油小于总的消耗那一定是走不完的。其次判断,过程中是否剩的油会小于0,如果小于0 那只能从下一个station开始。遍历一遍即可得到答案。
1. compare total gas and total cost, if total gas<total cost
return -1
2. iterate the whole station, rest+=gas[i]-cost[i] if rest<0, search start from the next i
return station
class Solution: # @param gas, a list of integers # @param cost, a list of integers # @return an integer def canCompleteCircuit(self, gas, cost): if sum(gas)<sum(cost): return -1 else: pre=0 rest=0 station=0 for index in range(len(gas)): rest+=gas[index]-cost[index] if rest<0: pre+=rest rest=0 station=index+1 return station
原文地址:http://blog.csdn.net/hyperbolechi/article/details/42879841