LeetCode之Gas Station

/*设置两个两个变量，用sum变量表示当前出发的点是否可行，total变量表示整个方法是否可行。方法参考自：https://github.com/soulmachine/leetcode*/  class Solution {public:    int canCompleteCircuit(vector<int> &gas, vector<int> &cost) {        int sum(0), total(0);        int start(-1);        for(int i = 0; i < gas.size(); ++i){            sum += gas[i] - cost[i];             total += gas[i] - cost[i];            if(sum < 0){                start = i;                sum = 0;            }        }        return total >= 0 ? start + 1 : -1;    }};