归并排序（Merge sort，即合并排序）是建立在归并操作上的一种有效的排序算法。该算法是采用分治法（Divide and Conquer）的一个非常典型的应用。其时间复杂度为O(n)O（最优）、(nlog n)（最差）。-Merge sort (Merge sort, that is, merge sort) an efficient sorting algorithm is merge operation. The algorithm is a typical application of the divide-and-conquer method (Divide and Conquer). Its time complexity is O (n) O (optimal) (nlog n) (worst).