134.加油站
力扣链接
 
class Solution:
    def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int:
        curSum = 0  # 当前累计的剩余油量
        totalSum = 0  # 总剩余油量
        start = 0  # 起始位置
        
        for i in range(len(gas)):
            curSum += gas[i] - cost[i]
            totalSum += gas[i] - cost[i]
            
            if curSum < 0:  # 当前累计剩余油量curSum小于0
                start = i + 1  # 起始位置更新为i+1
                curSum = 0  # curSum重新从0开始累计
        
        if totalSum < 0:
            return -1  # 总剩余油量totalSum小于0,说明无法环绕一圈
        return start



















