Continuous Subarray Sum

 1 public class Solution {
 2     /**
 3      * @param A an integer array
 4      * @return  A list of integers includes the index of the first number and the index of the last number
 5      * cnblogs.com/beiyeqingteng/
 6      */
 7     public ArrayList<Integer> continuousSubarraySum(int[] A) {
 8         if (A == null || A.length == 0) return null;
 9         
10         ArrayList<Integer> list = new ArrayList<Integer>();
11         // initialization
12         int preMax = A[0];
13         int startIndex = 0;
14         int tempMax = A[0];
15         list.add(0);
16         list.add(0);
17         
18         for (int i = 1; i < A.length; i++) {
19             if (preMax < 0) {
20                 preMax = A[i];
21                 startIndex = i;
22             } else {
23                 preMax = A[i] + preMax;
24             }
25             // update
26             if (preMax > tempMax) {
27                 list.clear();
28                 list.add(startIndex);
29                 list.add(i);
30                 tempMax = preMax;
31             }
32         }
33         return list;
34     } 
35 }