The main goal is to sort data on a stack, with a limited set of instructions, using the lowest possible number of actions. To succeed you’ll have to manipulate various types of algorithms and choose the one (of many) most appropriate solution for an optimized data sorting.

Pull files ↙️

git clone --recursive https://github.com/ailopez-o/42Barcelona-Push_swap.git

Compile both push_swap & checker ↙️

$ make

$>ARG="4 67 3 87 23"; ./push_swap $ARG | wc -l
6
$>ARG="4 67 3 87 23"; ./push_swap $ARG | ./my_checker $ARG
OK
$>

$>ARG="-g 4 67 3 87 23"; ./push_swap $ARG

All functions are created in accordance with Norm.

!NOTE
Because of 42 School norm requirements:

• All variables are declared and aligned at the top of each function
  
• Each function can't have more then 25 lines of code
  
• C style code commenting is forbidden
  
• Project should be created just with allowed functions otherwise it's cheating.
  

• The game is composed of 2 stacks named a and b.
  
• To start with:
  ◦ a contains a random number of either positive or negative numbers without any duplicates.
  ◦ b is empty
  
• The goal is to sort in ascending order numbers into stack a.
  
• To do this you have the following operations at your disposal:
  

-------------------------------------------------------------------------------------------------------
Init a and b:
2
1
3
6
8
5
_ _
a b
-------------------------------------------------------------------------------------------------------
Exec sa:
1
2
3
6
8
5
_ _
a b
-------------------------------------------------------------------------------------------------------
Exec pb pb pb:
6 3
5 2
8 1
_ _
a b
-------------------------------------------------------------------------------------------------------
Exec ra rb (equiv. to rr):
5 2
8 1
6 3
_ _
a b
-------------------------------------------------------------------------------------------------------
Exec rra rrb (equiv. to rrr):
6 3
5 2
8 1
_ _
a b
-------------------------------------------------------------------------------------------------------
Exec sa:
5 3
6 2
8 1
_ _
a b
-------------------------------------------------------------------------------------------------------
Exec pa pa pa:
1
2
3
5
6
8
_ _
a b 
-------------------------------------------------------------------------------------------------------

This example sort integers from a in 12 instructions.

• You have to write a program named checker, which will get as an argument the stack a formatted as a list of integers. The first argument should be at the top of the stack (be careful about the order). If no argument is given checker stops and displays nothing.
• Checker will then wait and read instructions on the standard input, each instruction will be followed by ’\n’. Once all the instructions have been read, checker will execute them on the stack received as an argument.
• If after executing those instructions, stack a is actually sorted and b is empty, then checker must display "OK" followed by a ’\n’ on the standard output. In every other case, checker must display "KO" followed by a ’\n’ on the standard output.
• In case of error, you must display Error followed by a ’\n’ on the standard error. Errors include for example: some arguments are not integers, some arguments are bigger than an integer, there are duplicates, an instruction don’t exist and/or is incorrectly formatted.

$>./checker 3 2 1 0
rra
pb
sa
rra
pa
OK
$>./checker 3 2 1 0
sa
rra
pb
KO
$>./checker 3 2 one 0
Error

• You have to write a program named push_swap which will receive as an argument the stack a formatted as a list of integers. The first argument should be at the top of the stack (be careful about the order).
• The program must display the smallest list of instructions possible to sort the stack a, the smallest number being at the top.
• Instructions must be separaed by a ’\n’ and nothing else.
• The goal is to sort the stack with the minimum possible number of operations. During defence we’ll compare the number of instructions your program found with a maximum number of operation tolerated. If your program either displays a list too big or if the list isn’t sorted properly, you’ll get no points.
• In case of error, you must display Error followed by a ’\n’ on the standard error. Errors include for example: some arguments aren’t integers, some arguments are bigger than an integer, and/or there are duplicates.

$>./push_swap 2 1 3 6 5 8
sa
pb
pb
pb
sa
pa
pa
pa
$>./push_swap 0 one 2 3
Error
$>

$>ARG="4 67 3 87 23"; ./push_swap $ARG | wc -l
6
$>ARG="4 67 3 87 23"; ./push_swap $ARG | ./checker $ARG
OK
$>

• 42 Push-Swap notion

• Least amount of moves

• Example and Pyviz

• VIDEO https://www.youtube.com/watch?v=7KW59UO55TQ

• Sort Algorithm:

  • https://lamfo-unb.github.io/2019/04/21/Sorting-algorithms/
  • https://zainab-dnaya.medium.com/fastest-push-swap-algorithm-2f510028602b
  • Radix: https://medium.com/nerd-for-tech/push-swap-tutorial-fa746e6aba1e

• Push_Swap testers:

  • https://github.com/lmalki-h/push_swap_tester
  • https://github.com/laisarena/push_swap_tester
  • https://github.com/LeoFu9487/push_swap_tester

• Visualizer:

  • https://github.com/o-reo/push_swap_visualizer