push_swap

push_swap is a 42 school algorithm project where we must sort a given list of random numbers with a limited set of instructions, using the lowest possible number of actions.

Usage

Use make to compile.

Then run it with :

./push_swap <numbers>

The numbers provided can be positive or negative integers. There must not be any duplicates. For example :

./push_swap 9 0 -217 2147483647 -2147483648

If the arguments are valid, the program will output the most efficient list of actions to sort the list.

The program can be checked with the provided checker, like this :

ARG="3 0 9 2 -1"; ./push_swap $ARG | ./checker $ARG

Push_Swap Rules

The program is only allowed two stacks to work with, stack A and stack B. All the numbers are initially added to stack A, and B is empty.

The possible actions are:

• 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.
• 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.
• ra (rotate A): Shift all elements of stack A up by 1. The first element becomes the last one.
• rb (rotate B): Shift all elements of stack B up by 1. The first element becomes the last one.
• rr: ra and rb at the same time.
• rra (reverse rotate A): Shift all elements of stack A down by 1. The last element becomes the first one.
• rrb (reverse rotate B): Shift all elements of stack b down by 1. The last element becomes the first one.
• rrr : rra and rrb at the same time.