Make stack sorted by using these commands.
- sa : swap a - swap the first 2 elements at the top of stack a. Do nothing if there is only one or no elements).
- sb : swap b - swap the first 2 elements at the top of stack b. Do nothing if there is only one or no elements).
- ss : sa and sb at the same time.
- pa : push a - take the first element at the top of b and put it at the top of a. Do nothing if b is empty.
- pb : push b - take the first element at the top of a and put it at the top of b. Do nothing if a is empty.
- ra : rotate a - shift up all elements of stack a by 1. The first element becomes the last one.
- rb : rotate b - shift up all elements of stack b by 1. The first element becomes the last one.
- rr : ra and rb at the same time.
- rra : reverse rotate a - shift down all elements of stack a by 1. The last element becomes the first one.
- rrb : reverse rotate b - shift down all elements of stack b by 1. The last element becomes the first one.
- rrr : rra and rrb at the same time.
This push_swap is based on insertion sort algorithm. But not 100% of insertion sort algorithm, 80% of insertion sort and 20% of greedy algorithm.