Please download and read:
Introduction to Algorithms, Third Edition,
Chapter 27 Multithreaded Algorithms
by Thomas H. Cormen, Charles E. Leiserson, Ronald L. Rivest, Clifford Stein
at:
Intro To Algorithms
course note: https://s3.amazonaws.com/content.udacity-data.com/courses/gt-cse6220/Course+Notes/Lesson1-3MergeSortNotes.pdf
what if ???
https://www.cnblogs.com/tuding/p/7335853.html