lintcode-medium-Continuous Subarray Sum

public class Solution {
    /**
     * @param A an integer array
     * @return  A list of integers includes the index of the first number and the index of the last number
     */
    public ArrayList<Integer> continuousSubarraySum(int[] A) {
        // Write your code here
        
        ArrayList<Integer> result = new ArrayList<Integer>();
        
        if(A == null || A.length == 0)
            return result;
        
        int index1 = 0;
        int index2 = 0;
        int sum = A[0];
        int max = A[0];
        int res1 = 0;
        int res2 = 0;
        
        for(int i = 1; i < A.length; i++){
            if(sum < 0){
                sum = 0;
                index1 = i;
                index2 = i;
            }
            
            sum += A[i];

            if(sum > max){
                max = sum;
                index2 = i;
                res1 = index1;
                res2 = index2;
            }
        }
        
        result.add(res1);
        result.add(res2);
        return result;
    }
}