LintCode-187. 加油站

public class Solution {
    /**
     * @param gas: An array of integers
     * @param cost: An array of integers
     * @return: An integer
     */
    public int canCompleteCircuit(int[] gas, int[] cost) {
        // write your code here
        for(int i = 0; i < gas.length; i++){
            int tank = 0;
            for(int j = 0; j < gas.length; j++){
                tank += gas[(i + j) % gas.length];
                tank -= cost[(i + j) % gas.length];
                if(tank < 0){
                    break;
                }
            }
            if(tank >= 0) return i;
        }
        return -1;
    }
}