134-Gas-Station.py

class Solution:
    def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int:     
        start, end = len(gas) - 1, 0
        total = gas[start] - cost[start]
        
        while start >= end:
            while total < 0 and start >= end:
                start -= 1
                total += (gas[start] - cost[start])
            if start == end:
                return start   
            total += (gas[end] - cost[end])
            end += 1
        return -1