Gas Station

public class Solution {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        int total=0, curRem=0, curSum=0,start=0;
        for(int i=0;i<gas.length;i++){
            curRem = gas[i]-cost[i];
            if(curSum>=0){
                curSum += curRem;
            }else{
                curSum = curRem;
                start = i;
            }
            total += curRem;
        }
        return total<0? -1: start;
    }
}