标签：style c class blog code java
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.
题解： 与经典的最大字段和问题类似，采用贪心策略。
1 class Solution { 2 public: 3 int canCompleteCircuit(vector<int> &gas, vector<int> &cost) { 4 int station = gas.size(); 5 int i,sum=0,start=0,total=0; 6 7 for(i=0;i<station;i++) 8 gas[i]-=cost[i]; 9 10 for(i=0;i<station;i++) total+=gas[i]; 11 if(total<0) return -1; 12 13 // 与求最大子段和类似，使用贪心策略 14 for(i=0;i<station;i++) 15 { 16 sum+= gas[i]; 17 if(sum<0) 18 { 19 start=i+1; // 如果当前和为负数，选择下一个元素作为起点 20 sum=0; 21 } 22 } 23 return start; 24 } 25 };
类似一题： Maximum Subarray : http://www.cnblogs.com/double-win/p/3746672.html
LeetCode：Gas Station 题解,布布扣,bubuko.com
标签：style c class blog code java
原文地址：http://www.cnblogs.com/double-win/p/3746637.html
