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libft/ft_priority_queue/ft_priority_queue.c

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+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_priority_queue.c                                :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: thrieg <thrieg@student.42mulhouse.fr>      +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/11/19 14:51:23 by thrieg            #+#    #+#             */
+/*   Updated: 2025/02/16 19:07:06 by thrieg           ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "ft_priority_queue_private.h"
+
+void	ft_insert_pq(t_priority_queue *pq, void *data, size_t priority)
+{
+	t_priority_queue_node	new_node;
+
+	if (pq->size >= pq->capacity)
+		ft_resize_pq(pq);
+	new_node.data = data;
+	new_node.priority = priority;
+	pq->nodes[pq->size] = new_node;
+	pq->size++;
+	heapify_up(pq, pq->size - 1);
+}
+
+t_priority_queue	*create_priority_queue(
+int capacity,
+int (*compare)(void *, void *))
+{
+	t_priority_queue	*pq;
+
+	pq = malloc(sizeof(t_priority_queue));
+	if (!pq)
+		return (NULL);
+	pq->nodes = malloc(capacity * sizeof(t_priority_queue_node));
+	if (!pq->nodes)
+		return (free(pq), NULL);
+	pq->size = 0;
+	pq->capacity = capacity;
+	pq->compare = compare;
+	return (pq);
+}
+
+void	*peek(t_priority_queue *pq)
+{
+	if (pq->size == 0)
+		return (NULL);
+	return (pq->nodes[0].data);
+}
+
+void	*dequeue(t_priority_queue *pq)
+{
+	void	*ret;
+
+	if (pq->size == 0)
+		return (NULL);
+	ret = pq->nodes[0].data;
+	pq->nodes[0] = pq->nodes[pq->size - 1];
+	pq->size--;
+	heapify_down(pq, 0);
+	ft_shrink_pq(pq);
+	return (ret);
+}
+
+void	free_pq(t_priority_queue *pq)
+{
+	free(pq->nodes);
+	free(pq);
+}

libft/ft_priority_queue/ft_priority_queue_private.h

@@ -0,0 +1,26 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_priority_queue_private.h                        :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: thrieg <thrieg@student.42mulhouse.fr>      +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/11/19 16:41:11 by thrieg            #+#    #+#             */
+/*   Updated: 2025/02/16 19:07:08 by thrieg           ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#ifndef FT_PRIORITY_QUEUE_PRIVATE_H
+# define FT_PRIORITY_QUEUE_PRIVATE_H
+
+# include "../ft_priority_queue.h"
+
+void	heapify_up(t_priority_queue *pq, size_t index);
+
+void	heapify_down(t_priority_queue *pq, size_t index);
+
+void	ft_resize_pq(t_priority_queue *pq);
+
+void	ft_shrink_pq(t_priority_queue *pq);
+
+#endif

libft/ft_priority_queue/ft_priority_queue_utils.c

@@ -0,0 +1,118 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_priority_queue_utils.c                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: thrieg <thrieg@student.42mulhouse.fr>      +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/11/19 16:00:58 by thrieg            #+#    #+#             */
+/*   Updated: 2025/02/16 19:07:01 by thrieg           ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "ft_priority_queue_private.h"
+#include "../ft_printf/ft_printf.h"
+
+static inline void	pq_swap(t_priority_queue_node *a, t_priority_queue_node *b)
+{
+	t_priority_queue_node	temp;
+
+	temp = *a;
+	*a = *b;
+	*b = temp;
+}
+
+void	heapify_up(t_priority_queue *pq, size_t index)
+{
+	size_t	parent;
+
+	while (index > 0)
+	{
+		parent = (index - 1) / 2;
+		if (pq->nodes[index].priority < pq->nodes[parent].priority)
+		{
+			pq_swap(&pq->nodes[index], &pq->nodes[parent]);
+			index = parent;
+		}
+		else if (pq->nodes[index].priority == pq->nodes[parent].priority
+			&& pq->compare(pq->nodes[index].data, pq->nodes[parent].data) < 0)
+		{
+			pq_swap(&pq->nodes[index], &pq->nodes[parent]);
+			index = parent;
+		}
+		else
+		{
+			break ;
+		}
+	}
+}
+
+void	heapify_down(t_priority_queue *pq, size_t index)
+{
+	size_t	smallest;
+	size_t	left;
+	size_t	right;
+
+	smallest = index;
+	left = 2 * index + 1;
+	right = 2 * index + 2;
+	if (left < pq->size
+		&& ((pq->nodes[left].priority < pq->nodes[smallest].priority)
+			|| (pq->compare(pq->nodes[left].data,
+					pq->nodes[smallest].data) < 0)))
+		smallest = left;
+	if (right < pq->size
+		&& ((pq->nodes[right].priority < pq->nodes[smallest].priority)
+			|| (pq->compare(pq->nodes[right].data,
+					pq->nodes[smallest].data) < 0)))
+		smallest = right;
+	if (smallest != index)
+	{
+		pq_swap(&pq->nodes[index], &pq->nodes[smallest]);
+		heapify_down(pq, smallest);
+	}
+}
+
+void	ft_resize_pq(t_priority_queue *pq)
+{
+	size_t					new_capacity;
+	t_priority_queue_node	*new_nodes;
+	size_t					i;
+
+	new_capacity = pq->capacity * 2;
+	new_nodes = malloc(new_capacity * sizeof(t_priority_queue_node));
+	if (!new_nodes)
+		return ;
+	i = 0;
+	while (i < pq->size)
+	{
+		new_nodes[i] = pq->nodes[i];
+		i++;
+	}
+	free(pq->nodes);
+	pq->nodes = new_nodes;
+	pq->capacity = new_capacity;
+}
+
+void	ft_shrink_pq(t_priority_queue *pq)
+{
+	size_t					new_capacity;
+	t_priority_queue_node	*new_nodes;
+	size_t					i;
+
+	if (pq->size >= pq->capacity / 4 || pq->capacity <= 4)
+		return ;
+	new_capacity = pq->capacity / 2;
+	new_nodes = malloc(new_capacity * sizeof(t_priority_queue_node));
+	if (!new_nodes)
+		return ;
+	i = 0;
+	while (i < pq->size)
+	{
+		new_nodes[i] = pq->nodes[i];
+		i++;
+	}
+	free(pq->nodes);
+	pq->nodes = new_nodes;
+	pq->capacity = new_capacity;
+}