题解 | #加油站#

#
# 
# @param gas int整型一维数组 
# @param cost int整型一维数组 
# @return int整型
#
class Solution:
    def canCompleteCircuit(self , gas , cost ):
        # write code here
        b=[]
        for i in range(len(gas)):
            b.append(gas[i]-cost[i])
        if max(b)<0:
            return -1
        i=b.index(max(b))
        while(i<len(gas)):
            next=(i+1)%len(gas)
            curOil=b[i]
            while(next!=i and next<len(gas)):
                curOil +=b[next]
                if curOil<0:
                    break
                next=(next+1)%len(gas)
            if curOil>=0:
                return i
            i += 1
        return -1