Maximum Subarray (JAVA)

时间：2014-10-09 00:23:07 收藏：0 阅读：218

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.

 1  public static int maxSubArray(int[] A) 
 2      {
 3             int max=A[0];
 4             for(int i=0;i<A.length;i++)
 5             {
 6                 int sum=0;
 7                 for(int j=i;j<A.length;j++)
 8                 {
 9                     sum+=A[j];
10                     if(sum>max)12                         max=sum;15                 }
16             }
17                 
18          return max;
19       }

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;
     }