### Problem

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.

### JavaScript Code

```function canCompleteCircuit(gas, cost) {
var sumRemaining = 0; // track current remaining
var total = 0; // track total remaining
var start = 0;

for (var i = 0; i < gas.length; i++) {
var remaining = gas[i] - cost[i];

//if sum remaining of (i-1) >= 0, continue
if (sumRemaining >= 0) {
sumRemaining += remaining;
//otherwise, reset start index to be current
} else {
sumRemaining = remaining;
start = i;
}
total += remaining;
}

if (total >= 0){
return start;
}else{
return -1;
}
}
console.log(canCompleteCircuit([1,2,3,4,5],[1,3,2,4,5]));
``` Srinivas Dasari find me on facebook follow me on twitter