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.
1 public class Solution { 2 public int canCompleteCircuit(int[] gas, int[] cost) { 3 int starts = 0; 4 int sum1 = 0; 5 int sum2 = 0; 6 for(int i = 0; i < gas.length; ++i){ 7 sum2 += gas[i] - cost[i]; 8 if(sum2 < 0){ 9 sum1 += sum2; 10 sum2 = 0; 11 starts = i + 1; 12 } 13 } 14 if(sum1 + sum2 <0) 15 starts = -1; 16 return starts; 17 } 18 }
原文：http://www.cnblogs.com/averillzheng/p/3536711.html