reverse_rotations.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   reverse_rotations.c                                :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: rjobert <rjobert@student.42barcelo>        +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2023/06/30 18:59:47 by rjobert           #+#    #+#             */
/*   Updated: 2023/07/15 16:25:09 by rjobert          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "push_swap.h"

/* how to reverse rotate (last node become first)
1- we go to the almost last node
2 - we save in temp the last node
3 - we make the almost last node the lst (point null)
4 - we make temp point to head and head = temp */
void	reverse_rotate(t_list **stack)
{
	t_list	*head;
	t_list	*temp;
	t_list	*save;

	if (!*stack || !(*stack)->next)
		return ;
	head = *stack;
	save = *stack;
	while (head->next->next)
		head = head->next;
	temp = head->next;
	temp->next = save;
	save->prev = temp;
	head->next = NULL;
	temp->prev = NULL;
	head = temp;
	*stack = head;
}

void	rra(t_list **a, int n)
{
	reverse_rotate(a);
	if (n != 0)
		ft_putstr("rra\n");
}

void	rrb(t_list **b, int n)
{
	reverse_rotate(b);
	if (n != 0)
		ft_putstr("rrb\n");
}

void	rrr(t_list **a, t_list **b, int n)
{
	reverse_rotate(a);
	reverse_rotate(b);
	if (n != 0)
		ft_putstr("rrr\n");
}