Gas station
There areNGas stations along a circular route, where the amount of gas at StationIIsgas[i]
.
You have a car with an unlimited gas tank and it costscost[i]
Of gas to travel from StationITo 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.
Algorithm ideas:
Find the gas stations that can start safely, and then start from these safe gas stations one by one.
The Code is as follows:
1 public class Solution { 2 public int canCompleteCircuit(int[] gas, int[] cost) { 3 int[] stations = new int[gas.length]; 4 int count = gas.length,index = 0; 5 for(int i = 0; i < count;i++){ 6 if(gas[i] >= cost[i]){ 7 stations[index++] = i; 8 } 9 }10 breakable:11 for(int i = 0; i < index; i++){12 int gasCount = 0;13 int costCount = 0;14 for(int j = stations[i]; j < count + stations[i]; j++){15 gasCount += gas[j % count];16 costCount += cost[j % count];17 if(costCount > gasCount) continue breakable;18 }19 return stations[i];20 }21 return -1;22 }23 }