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 sum = 0;
int total = 0;
int j = -1;
int n = gas.size();
for(int i=0;i<n;i++)
{
sum += gas[i] - cost[i];
total += gas[i] - cost[i];
if(sum<0)
{
sum = 0;
j = i;
}
}
if(total<0)
return -1;
return j+1;
}
};
