# 0134. Gas Station
###### tags: `Leetcode` `Medium` `TikTok`
Link: https://leetcode.com/problems/gas-station/
## 思路
需要数学证明的一道题
要证明出如果从A开始到不了B，那么从A和B当中任何一个点开始都到不了B
所以只需要遍历一遍，如果发现中途currGas<0，那就将下一个点设为起始点
判断究竟能不能绕一圈：totalgas-totalcost>=0
## Code

class Solution {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        int gasStation = 0;
        int totalGas = 0;
        int currGas = 0;
        for(int i = 0;i < gas.length;i++){
            totalGas += gas[i]-cost[i];
            currGas += gas[i]-cost[i];
            if(currGas<0){
                gasStation = i+1;
                currGas = 0;
            }
        }
        return totalGas>=0?gasStation:-1;
    }
}