Data Structures, Algorithms, & Applications in C++
Chapter 18, Exercise 13

initial       [11] [3] [8] [7] [5] [10] [0] [9] [4] [2] [6] [1]
merge to b    [3   11] [7   8] [5   10] [0   9] [2   4] [1   6]
merge to a    [3    7   8  11] [0    5   9  10] [1   2   4   6]
merge to b    [0    3   5   7   8    9  10  11] [1   2   4   6]
merge to a    [0    1   2   3   4    5   6   7   8   9  10  11]