Maximum Subarray (JAVA)

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [−2,1,−3,4,−1,2,1,−5,4],
the contiguous subarray [4,−1,2,1] has the largest sum = 6.

  public static int maxSubArray(int[] A)
      {
             int max=A[0];
             for(int i=0;i<A.length;i++)
             {
                 int sum=0;
                 for(int j=i;j<A.length;j++)
                 {
                     sum+=A[j];
                     if(sum>max)                         max=sum;                 }
             }

          return max;
       }

O(n):

 public static int maxSubArray(int[] A)
     {
         int max=A[0];
         int sum=0;
         for(int i=0;i<A.length;i++)
         {
             sum+=A[i];
             if(sum>max)
                 max=sum;

             if(sum<0)
             sum=0;
         }
         return max;
     }