排序算法归并排序(递归)

归并排序(递归)

void MergeSort(int *A, int n){
  if(n == 1){
    return ;
  }
  int *C = new int[n];
  int l1 = n/2;
  int l2 = n-l1;
  MergeSort(A, l1);
  MergeSort(&A[l1], l2);
  for(int i = 0, j = l1, k = 0; k < n;){
    while(i!=l1 && j != n){
      if(A[i]<A[j]){
        C[k] = A[i];
	k++;
        i++;
      }else{
        C[k] = A[j];
        j++;
	k++;
      }
    }
    if(i == l1){
      C[k] = A[j];
      j++;
      k++;
    }else if(j == n){
      C[k] = A[i];
      i++;
      k++;
    }    
  }
  memcpy(A, C, sizeof(int)*n);  
  delete[] C;
  return ;
}