LeetCode Gas Station

最新推荐文章于 2019-10-23 11:28:34 发布

原创最新推荐文章于 2019-10-23 11:28:34 发布 · 280 阅读

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本文探讨了一个关于循环路线中油站的问题，即如何确定一辆充满无限油箱的车辆从哪个油站出发，可以完成一圈行驶而不耗尽油。通过分析给定的代码实现，解释了算法背后的逻辑和解决问题的方法。

题目：

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.

Note:
The solution is guaranteed to be unique.

class Solution {
public:
	int canCompleteCircuit(vector<int> &gas, vector<int> &cost) {
		int n = gas.size();
		int cur = 0;
		int total = 0;
		int res = -1;
		for (int i = 0; i < n; i++) {
			cur += gas[i] - cost[i];
			total += gas[i] - cost[i];
			if (cur < 0) {
				res = i;
				cur = 0;

			}
		}
		return total >= 0 ? res + 1 : -1;

	}
};