"""

```
def canCompleteCircuit(self, gas, cost):
circle = gas+gas
costs = cost+cost
capacity = 0
stations = 0
start_index = -1
for i in range(0,len(circle)):
if start_index == -1:
start_index = i
available = circle[i] + capacity
need = costs[i]
if available >= need:
newcapacity = circle[i] + capacity - costs[i]
capacity = newcapacity
stations += 1
else:
capacity = 0
stations = 0
start_index = -1
if stations == len(gas):
return start_index
return -1
```

"""