LeetCode OJ - Merge Sorted Array

原地归并。

下面是AC代码：

 1  public void merge(int A[], int m, int B[], int n) {

 2

 3          int len = A.length;

 4          //first copy m elements of A to the end of A

 5          for(int i=m-1,j = len-1;i>=0;i--){

 6              A[j--] = A[i];

 7          }

 8          //merge the A and B

 9          int startA = len - m;

10          int startB = 0;

11          int i = 0;

12          while(startA<len || startB<n){

13              while(startA<len&& startB<n && A[startA]<=B[startB])

14              {

15                  A[i++] = A[startA];

16                  startA++;

17              }

18              while(startA<len && startB<n && B[startB]<A[startA]){

19                  A[i++] = B[startB];

20                  startB++;

21              }

22              while(startA == len && startB<n){

23                  A[i++] = B[startB++];

24              }

25              while(startB == n  && startA<len){

26                  A[i++] = A[startA++];

27              }

28          }

29      }

 1 /**

 2       * second method very nice . from the end to start

 3       * @param A

 4       * @param m

 5       * @param B

 6       * @param n

 7       */

 8      public void merge2(int A[], int m, int B[], int n){

 9          int i = m+n-1;

10          while(i>=0 &&( n>=0 || m>=0)){

11              A[i--] = m-1 < 0? B[(n--)-1]:

12                  n-1 < 0? A[(m--)-1] : A[m-1]>=B[n-1]? A[(m--)-1]:B[(n--)-1];

13          }

14      }

LeetCode OJ - Merge Sorted Array