Gas Station

最新推荐文章于 2024-10-12 23:30:39 发布

weixin_30527323

最新推荐文章于 2024-10-12 23:30:39 发布

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原文链接：http://www.cnblogs.com/zhengjiankang/p/3682324.html

There are N gas stations along a circular route, where the amount of gas at station i is gas[i].
You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from station i to its next station (i+1). You begin the journey with an empty tank at one of the gas stations.
Return the starting gas station's index if you can travel around the circuit once, otherwise return -1.
The solution is guaranteed to be unique.

Solution: ...

 1 class Solution {
 2 public:
 3     int canCompleteCircuit(vector<int> &gas, vector<int> &cost) {
 4         int N = gas.size();
 5         int res = 0, min = gas[0] - cost[0], sum = min;
 6         for (int i = 1; i < N; ++i)
 7         {
 8             sum += gas[i] - cost[i];
 9             if (sum < min) { // not understand it completely
10                 min = sum;
11                 res = i;
12             }
13         }
14         return sum >= 0 ? (res + 1) % N : -1;
15     }
16 };