题目链接

贪心

class Solution {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        int curSum = 0;
        int totalSum = 0;
        int start = 0;
        for(int i = 0; i < gas.length; i++){
            // 当前剩油量
            curSum += gas[i] - cost[i];
            // 总剩油量
            totalSum += gas[i] - cost[i];
            // 当前剩油量小于零则区间[0,i]不能作为起点
            if(curSum < 0){
                start = i + 1;
                curSum = 0;
            }
        }
        if(totalSum < 0){
            return -1;
        }
        return start;
    }
}