Given a list of elements, does a shuffling algorithm exist that will guarantee that eventually a selected half portion will be on one side, and the remainder on the other?
Example: { 4, 3, 10, 7, 2, 9, 6, 8, 1, 5 }
Given the set above, I'd like to have a mixing algorithm that eventually moves the marked ones to the left, even though the algorithm itself has no idea what is and isn't "marked."
{ 4, 3, 10, 7, 2, 9, 6, 8, 1, 5 }
X X X X X
Acceptable results would be:
{ 4, 10, 9, 6, 1, 3, 7, 2, 8, 5 }
{ 1, 9, 10, 4, 6, 2, 8, 5, 7, 3 }
{ 1, 4, 9, 10, 6, 3, 7, 5, 8, 2 } etc
Difficulty: The algorithm shouldn't use random numbers to mix the contents, it should be an iterative process. So Fisher-Yates is out.
Would std::next_permutation() be what you want? (Since it creates all possible permutations, it will, eventually, also put the marked once to the left.)