数组中最大子数组求和问题

使用暴力求解法，算出所有子数组的和，比较大小，得出结果，代码如下

 1 package cn.edu.niit.test2;
 2 
 3 /**
 4  * Created by Wang Yifan on 2017/03/17.
 5  */
 6 
 7 public class Test2 {
 8     int MaxSubArray(int[] A, int n)
 9     {
10         int maxSum = A[0];  //全负情况，返回最大负数
11         int currSum = 0;
12         for (int i = 0; i < n; i++)
13         {
14             for (int j = i; j < n; j++)
15             {
16                 for (int k = i; k <= j; k++)
17                 {
18                     currSum += A[k];
19                 }
20                 if (currSum > maxSum)
21                     maxSum = currSum;
22 
23                 currSum = 0;
24             }
25         }
26         return maxSum;
27     }
28 }

对此方法进行测试，验证算法是否正确，代码如下

 1 package cn.edu.niit.test2;
 2 
 3 import org.junit.Before;
 4 import org.junit.Test;
 5 
 6 import static org.junit.Assert.*;
 7 
 8 /**
 9  * Created by Wang Yifan on 2017/03/17.
10  */
11 
12 public class Test2Test {
13     private  Test2 Array;
14 
15     @Before
16     public void setUp() throws Exception {
17         Array = new Test2();
18     }
19 
20     @Test
21     public void maxSubArray() throws Exception {
22         int []Array1={-1,2,3,-4};
23         assertEquals(5d,Array.MaxSubArray(Array1,Array1.length),4);
24 
25         int []Array2={-1,2,-5,3,-4};
26         assertEquals(3d,Array.MaxSubArray(Array2,Array2.length),5);
27 
28         int []Array3={-1,20,-5,30,-4};
29         assertEquals(45d,Array.MaxSubArray(Array3,Array3.length),5);
30 
31         int []Array4={-2,-3,-5,-1,-9};
32         assertEquals(-1d,Array.MaxSubArray(Array4,Array4.length),5);
33     }
34 }

验证结果如下图，算法正确

posted @ 2017-03-18 02:12  Wwwyyf  阅读(291)  评论(0)  编辑  收藏  举报