Compile with:
g++ -std=c++14 -Irange-v3/include main.cpp
Example input/output:
We're going to create k sorted arrays each containing n integers
between 1 and 100 (inclusive)
k = 5
n = 5
in[0] = [ 19, 33, 38, 52, 100]
in[1] = [ 1, 29, 77, 85, 100]
in[2] = [ 5, 6, 60, 71, 74]
in[3] = [ 46, 60, 64, 73, 80]
in[4] = [ 10, 54, 56, 79, 89]
out[] = [1, 5, 6, 10, 19, 29, 33, 38, 46, 52, 54, 56, 60, 60, 64, 71, 73, 74, 77, 79, 80, 85, 89, 100, 100]