http://www.geeksforgeeks.org/find-a-tour-that-visits-all-stations/

maxDistance.java

class GasStation {
 
    public static int canCompleteCircuit(int[] gas, int[] cost) 
    {
        if(gas == null || cost == null) return -1;
 
        int total = 0;
        int upToNow = 0;
        int startPos = 0;
        for(int i=0; i<gas.length; i++) 
        {
            int delta = gas[i] - cost[i];
            if(upToNow >= 0)   
            {
                upToNow += delta;
            } 
            else 
            {
                upToNow = delta;
                startPos = i;
            }
            total += delta;
            // System.out.println( "Delta: " + delta + " Total: " + total );
        }
 
        return total >= 0 ? startPos : -1;
    }
 
    public static void main(String[] args) 
    {
        int[] gas = {6,3,7};
        int[] cost = {4,6,3};
        System.out.println(canCompleteCircuit(gas, cost));
    }
}