/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   permutations.c                                     :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: kjimenez <marvin@42.fr>                    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/07/24 14:35:22 by kjimenez          #+#    #+#             */
/*   Updated: 2022/07/24 14:35:25 by kjimenez         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include <stdlib.h>
#include "lib.h"

int	perm_next(int n[])
{
	int	tail;
	int	i;
	int	j;

	i = 3;
	while (i > 0 && n[i - 1] >= n[i])
		i--;
	tail = i;
	if (tail > 0)
	{
		j = 3;
		while (j > tail && n[j] <= n[tail - 1])
			j--;
		ft_swap(&n[tail - 1], &n[j]);
	}
	i = tail;
	j = 3;
	while (i < j)
	{
		ft_swap(&n[i], &n[j]);
		i++;
		j--;
	}
	return (tail != 0);
}

int	**generate_permutations(void)
{
	int	**permut;
	int	perm[4];
	int	i;
	int	j;

	permut = (int **) malloc(24 * sizeof(int *));
	j = 0;
	i = 0;
	while (++i <= 4)
		perm[i - 1] = i;
	while (1)
	{
		permut[j] = (int *) malloc(4 * sizeof(int));
		i = -1;
		while (++i < 4)
			permut[j][i] = perm[i];
		j++;
		if (!perm_next(perm))
			break ;
	}
	return (permut);
}