leetcode 日经贴，python code -Gas Station

Gas Station

class Solution:    # @param gas, a list of integers    # @param cost, a list of integers    # @return an integer    def canCompleteCircuit(self, gas, cost):        n = len(gas)        ret = -1        i = 0        while i < n:            reminder = 0            for j in range(n):                k = (i + j) % n                reminder += gas[k] - cost[k]                if reminder < 0:                    i = j + i + 1                    break            else:                ret = i                i = n        return ret