First, the algorithm ideas:
Divide and Conquer: vector LIST
Sequence into two // O (1)
Recursive sequence sorting // 2 x T (n / 2 )
The combined ordered sequence // O (n)
Second, for example as follows:
T (n) = 2 * T (n / 2) + O (n) T (n) = O (nlog (n)) can be solved using the replacement method; where O (n) are sorted merge two sub-sequences time.
Merging merge principle as follows:
Merging merge to achieve the following:
Open space to store the element B _elem [lo, mi) in, and _elem [mi, hi) elements do not need to open up the space for a new cache, only need to define a pointer pointing to this memory C on it.
Merging again improved:
Because C is a half of the A and B when fully depleted, need not perform A [i ++] = C [k ++]; C is no need to wait depleted, once depleted B is terminated. Therefore, changing the order of the two loop body, remove redundant logic.
Merging the complexity: the j + k as a whole, in the worst case, only O (n) is linear time.
