A program that attempts to find the minimum number of moves to sort a stack using a specific set of moves and one helper stack. The program outputs the shortest list of moves that it found. Includes a checker program that tests if the outputted list of instructions leads to a sorted stack.

The stack can be given as separate arguments or as a string.

The first number corresponding to the number at the top of the stack.

./push_swap 5 3 1 2 4

or

./push_swap "5 3 1 2 4"

The checker takes the same argument(s) as push_swap, then waits for sorting instructions from the standard input.

./checker 5 3 1 2 4

Especially for larger stacks, it is easiest to run by piping the output of push_swap to the checker.

ARGS="5 3 1 2 4"; ./push_swap $(ARGS) | ./checker $(ARGS)

• pa - pushed from stack b to stack a
• pb - pushed from stack a to stack b
• sa - swaps the top two elements of stack a
• sb - swaps the top two elements of stack b
• ss - performs sa and sb simultaneously
• ra - shifts all elements of stack a up one (first becomes last)
• rb - shifts all elements of stack b up one (first becomes last)
• rr - performs ra and rb simultaneously
• rra - shifts all elements of stack a down one (last becomes first)
• rrb - shifts all elements of stack a down one (last becomes first)
• rrr - performs rra and rrb simultaneously