[leetcode] Gas Station java

    public int canCompleteCircuit(int[] gas, int[] cost) {        int sum = 0;        int total = 0;        int lastPoint = 0;        for(int i = 0; i < gas.length; i ++)        {        sum += gas[i] - cost[i];        total += gas[i] - cost[i];        if(sum < 0)        {        sum = 0;        lastPoint = i+1;        }        }                return (total >= 0) ? lastPoint : -1;    }