*leetcode #134 in cpp

最新推荐文章于 2020-05-10 16:22:47 发布

原创最新推荐文章于 2020-05-10 16:22:47 发布 · 187 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#cpp #leetcode

interview 专栏收录该内容

135 篇文章

订阅专栏

本文探讨了一个经典的计算机科学问题——环路加油站问题。该问题要求找到一条从某个加油站出发能够绕环路一周并返回起点的路径。解决方案采用了高效的算法来确定起始加油站的索引，若无法完成环路则返回-1。文章提供了详细的算法思路及C++实现代码。

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.

Solution:

http://bangbingsyb.blogspot.com/2014/11/leetcode-gas-station.html

Code:

class Solution {
public:
    int canCompleteCircuit(vector<int>& gas, vector<int>& cost) {
        int n = gas.size(); 
        int curSum = 0;
        int wholeSum = 0;
        int start =0;
        for(int i = 0; i < n; i ++){
            wholeSum += gas[i] - cost[i];
            curSum += gas[i] - cost[i];
            if(curSum < 0){
                start = i + 1; 
                curSum = 0;
            }
        }
        if(wholeSum < 0) return -1;
        else return start; 
        
    }
};